Once While Calibrating a Trans-Temporal Psychic Beacon Spatio-Locator
by Verity359
Summary: "Nothing said temporal paradox like running into your easily preventable half-human clone from the future and learning that he'd go on to steal your girlfriend." Donna gets her memories back, Rose and the metacrisis Doctor return from Pete's World, and the Tenth Doctor doesn't have to go anywhere he doesn't want to. (Rose/10)
1. Chapter 1

**Dedicated to my wonderful beta readers, LostInWho and JohnPaulGeorgeandRingo!**

**Huge thanks to LostInWho for beta reading my terrible, terrible first draft. She caught a thousand spelling/grammar/punctuation/mechanical problems and one frankly humongous character interaction problem in the plot, and I will be forever grateful!**

**JohnPaulGeorgeandRingo also helped me IMMENSELY by getting my dialogue (and much of Rose's personality) back on track, by pointing out where I sounded hopelessly American, and by getting me to actually describe places instead of just saying "it's a place."**

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Setting: Cardiff Rift, 2007.

The Doctor knew he had been spending too much time pining over Rose when he started to hallucinate her walking around the console room.

It was an overcast Friday, a little before noon, and the TARDIS was parked at Roald Dahl Plass, its usual place for a rift energy fuel up. The Doctor had been hiding out in his study, a room Martha hadn't yet discovered. Adventuring with the bright young doctor-in-training was usually a good way to keep himself from dwelling too long on the things he couldn't change, but right now he didn't really feel up to it. He just needed to be alone for a bit to tinker and think without making her ask more questions he didn't want to answer, or worse yet, making her feel like she wasn't good enough for him because she wasn't Rose.

To be perfectly honest, what with getting her stuck for three months in 1913 and then immediately getting her stuck again in 1969, he was amazed that she hadn't gotten fed up and left already. If he didn't shake this melancholy soon, he might finally end up pushing her too far, and end up all alone again. And that Donna Noble woman had been right – he wasn't good on his own.

It was in the middle of this moody reverie that the panel on the nearest wall chimed softly to let him know someone from outside had entered the TARDIS.

He glanced up from his tinkering, surprised. Normally the ship didn't bother to inform him when Martha came and went, and he couldn't imagine who else would be able to just walk right in.

The Doctor frowned and pulled a fold-away remote viewing monitor from the wall to check the live video-feed in the console room. When he saw who it was, he froze, dropping the half-disassembled Drahvin power converter he'd been working on with a clatter.

Rose Tyler, who he knew without a doubt was stuck forever in a parallel universe without a snowball's chance on Venus of ever returning to this world, was kneeling on the grate that served as the floor in the TARDIS console room, pulling up one of the panels with a hook he kept under the console for that purpose.

The Doctor reached forward from his chair and shakily grasped the monitor with both hands. She was back! No, no, wait, she couldn't be back. That was impossible! Wasn't it? It was! He _knew _he had tried everything. He'd spent two full years of his subjective linear timeline trying every single mad scheme he could think of to get her back before finally admitting to himself that the best he could manage was a holographic goodbye message.

Maybe this footage was old. Could the TARDIS' main computers be acting up, recycling old video footage from over a year ago? He yanked the control panel out of its slot in the wall and pulled up a systems check. Circular Gallifreyan writing informed him that all systems were performing normally. The TARDIS' energy cells were currently recharging on rift energy at 24%.

He whirled around again to the live video feed, dumbstruck, and stared at what could only bea sign that he'd gone round the bend. Meanwhile, his impossible former companion pulled up the grate, set it down to her right, and reached under the floorboards for one of the chests of gizmos and old knicknacks that he stored under there. She rummaged through it for a few seconds, quickly managed to locate the Argolin mobile neural interface array, and held it up to inspect it in the light of the time rotor.

That was when Martha abruptly walked smack-dab into the middle of the hallucination and jumped about a foot in the air. Her voice echoed out from the audio feed in the study.

"What the – how…? Who are you? How did you get in here?" she yelped.

Rose stared open-mouthed at Martha for a second. On the other side of the TARDIS, still staring gobsmacked at the monitor in his study, the Doctor shot to his feet.

She was _real!_ Hallucinations didn't interact with real people!

"Martha?" he heard Rose ask, bewildered. "It's me, Rose. We met, remember? But what are you…" Her voice trailed off as she looked around, _really _looked around at the tiny differences in detail in her surroundings, and comprehension dawned on her face. "Oh bloody hell, I've gone an' done it now." Eyes wide, she stumbled backwards down the ramp and bolted out of the TARDIS.

The Doctor vaulted over the armchair he'd just been sitting in and tore out of the room like a shot, careened through the corridors, flew through the console room (past a very confused Martha), and skidded out into the street. He paused only a second to look to see which way she'd gone, and, seeing her disappear round a corner down the street to his left, broke into an all-out sprint. She was fast, something he'd been glad of during their years of running from various monsters, but his longer legs allowed him to keep up and even gain on her slowly.

"Rose! Rose, wait!" he shouted desperately as she continued to sprint down Lloyd George Avenue.

"Oh, bugger," Rose mumbled as she ran, mentally kicking herself. Of course, he'd have noticed her. Instinctively, she'd headed north toward Canal Park (_now _she remembered parking there), but the wide pedestrian walkway lined with saplings and low shrubs on one side and the long, unbroken wall of pale brick apartments on the other offered no hiding places for her to duck into. He was gonna catch her at this rate. She kept running, but slowed down just enough to turn and shout back. "Doctor, you can't! You're gonna cross your own timeline! You have to go back-"

She caught a glimpse at his face then, and the forlorn abandonment she saw there brought her to a reluctant standstill. Already a bit out of breath from her run, she turned back and shook her head at her own stupidity as she headed toward him. _Oh, all right_, she thought to herself, _Sorry, Universe, but I can't very well leave him looking like that. You'll just have to deal with it this time._

The Doctor, getting his second wind now that he could see she was coming back, collided into her at top speed with an ecstatic grin on his face and swooped her up into a spinning hug.

"Rose, you're back, you came back, that's brilliant!" He set her down, but continued to crush her against his chest like a drowning man clutching a life preserver.

"My own Rose, defender of Earth, always doing the impossible. How did you do it? Or how will you do it, rather, if, as you said, I'm crossing my own timeline?"

"Doctor," she said, her smile pressed into the shoulder of his trench coat. Despite knowing that she shouldn't, and knowing that she had her own version of the Doctor just a little ways down the road, it was hard not to respond to his excitement, even though most of _her _adrenaline rush was based on the thought that the time-space continuum might rip apart at the seams any moment.

Her arms around his shoulders, Rose gave him a squeeze and then pulled back enough for them to look at each other.

"Doctor, I can't tell you anything. You aren't supposed to meet me yet." She suspected she'd just torn a hole in the fabric of space-time somewhere, but he was grinning ear to ear like a loon, and she felt her mouth twitch up at the corners despite herself. "Oh, but we've really done it now."

"You're from my future," he said. "You said 'yet.'"

"Yeah, I did."

"That means I'm going to see you again," he insisted for confirmation. "Am I here with you now?" He glanced around, scanning for some rival future self who might come any second to steal Rose away again.

"Yeah, but… Look, that's Martha in there, yeah? And she's actin' like she's never seen me before, which means you're still travelin' with her, and that means I've just botched everything up, big time. You've got to go back." She looked around the wide, smoothly paved thoroughfare uneasily. There wasn't much foot traffic yet, and the street was luckily mostly empty. "There could be reapers here any second just for telling you that much."

"You walked right into the TARDIS. I can't believe it." He seemed altogether too unconcerned, almost giddy. He bounced up and down like he might float away right off the surface of the Earth any second.

Rose wondered if maybe he'd been a little more emotionally unbalanced during his travels with Martha than the later him had let on.

"I did, yeah, but that's 'cos we always used to park there, and I forgot you set us down about half a mile away this time. An' anyway, I didn't think to wonder if there could be more than one TARDIS in the same place at the same time." She poked him in the chest with a fond but serious expression. "What were you thinking, landing twice in the same town on the same date? I mean, you're the one always goin' on about not being allowed to cross into one's own timeline once you're 'part of established events,' or whatever."

"Yeah, you'd think I'd manage to avoid that," the Doctor agreed as he continued to beam at Rose, much too happy to care about the details for the moment.

"Well, what are we gonna do? I don't want to cause a paradox. An' I suppose I'd better give you this back, too." She tried to hand him the neural interface array. "I meant to fetch it from our TARDIS – I mean the one in my time."

"Right, yeah," he hummed, ignoring the gizmo she offered. He preferred to keep his arms where they were, wrapped around her waist and clasped behind her back.

"Doctor."

"Yes?"

"I'm glad that you're happy to see me," she smiled sympathetically, "But can you concentrate for a minute? You do get that we might be rewriting our own history, here, yeah?"

"Absolutely."

"You have to take this and go back. I might be changing my own past just talkin' to you. I _know _I'm changing your past. You never once mentioned this, an' you _definitely _would've said."

"Well, that's all right. Future me probably just forgot the whole thing."

"What d'you mean, forgot? You mean like amnesia? Can Time Lords get amnesia?"

"When I need to, I can wipe my own memory. I probably end up doing that. That'd explain why _your_ me doesn't remember there being any risk of running into _this_ me here at this point in time and figured it'd be safe to land here for a refueling. He's got no idea he was already here."

"You can do that? Just forget, on purpose, just like that?"

"Course, I can! 'Do it all the time, in fact. Well, not all the time. Just when I run into my past and future selves. And I try to avoid that – 's not good for the space-time continuum. Not good for my brain, either, come to think of it." He frowned slightly.

"You run into your selves a lot, then?" she asked, bemused.

"No. Well, maybe. I wouldn't really know, would I? I might have met three future me's last week and wiped my own memory each time."

"Well, maybe you'd better go back to the TARDIS and do that, then. I don't want to risk the timelines any more than we already have."

The pain and longing from earlier reappeared on the Doctor's face. He looked at her like a man who'd just won the lottery, only to accidentally drop the ticket down a sewer drain.

"Rose, I don't have to go yet. Not when I just—it's been so long, Rose, and I thought I'd never—" He trailed off and raised his hand to tuck a few stray blonde strands of hair behind her ear. "Just stay with me a little while. A few hours. Tops! Then I promise I'll go back and forget everything."

Rose hesitated, glancing over his shoulder, past his TARDIS, where she knew another alleyway was concealing a second one – a new ship grown from a coral clipping of the first, not the future version of _this _Doctor's TARDIS like he was certainly assuming. And a little ways down the road behind her, in a closed-down pub, there waited a half-human Doctor who, she mused, you could also say was grown from a clipping of the old one. She didn't know what would happen if the old Doctor met the new new new Doctor and realized he wasn't a full Time Lord anymore. She wished their Pete's World cell phones were compatible with the towers in this universe so she could give her Doctor a call and ask him what to do. As it was, she supposed it was better not to lead the old Doctor back to her current one, and right now he looked like he'd follow her anywhere like a lost puppy.

"Yeah, um, I suppose we can do that… for a little while," she finally conceded a little uncertainly.

He looked so relieved that she felt almost guilty about not leaping tearfully into his arms the moment they'd met. But after all, from her perspective, she had just seen him five minutes ago when he'd asked her to run back and fetch a part from the TARDIS. Instead, she couldn't help thinking uncomfortably about how, two years from now in his timeline, he would get this exact same astounded, deliriously happy look on his face, run toward her, and immediately get shot by a Dalek. Then he'd inadvertantly cause a human-Time Lord metacrisis and have to send her away again with his duplicate, this time for good.

And now here she was unintentionally misleading his past self into thinking everything was going to be just fine. She tried not to let any of this show through shining eyes as she hugged him around the neck again.

"I missed you, y'know," she told him softly. "During the time we were apart. I never stopped looking for a way back through." _Her_ Doctor, the metacrisis one, was technically here hugging her right now too, she reminded herself firmly. It was _his _past she was holding as much as it was the other one's, since this was before part of his consciousness split off into that old hand. It would be silly to cry over the future of this younger Doctor when she knew one half of him was going to end up staying with her. It was a glass half full kind of situation. Just don't focus on the half that walked away.

"And you found me," he smiled reassuringly, catching the faint sorrow that hid behind her words and misreading its cause. He bowed his head into the side of her neck, breathing in the scent of her hair. "You've got me back, in your time."

She tried not to hear the rest of that thought in her mind: _Yeah, I've got one of you. But one of you didn't get me._


	2. Chapter 2

Martha, confused and slightly peeved at being brushed by like that without a word, went wandering down Lloyd George Avenue looking for the Doctor. She was sure he'd run this way.

"Doctor? Doctor, where've you gone?"

She walked to the end of the street and looked around without seeing a single sign of nonhuman life. She sighed.

"Nooo, don't mind me – I'll just wait around here. As usual," she muttered to herself.

As much as she loved traveling with the Doctor, the man could be infuriating. He was always taking off without warning, or spouting some kind of technical gibberish, or getting her stuck in some kind of disgusting alien smog or human waste clean-up job. What's more, he was completely oblivious to what trouble she might face or how she might feel in any situation. It never once seemed to occur to him that being female, black, or human might make a difference in how people treat you in certain eras. He was insufferable, exasperating, completely barmy… and also painfully brilliant, good looking, and reliable in a pinch. She sighed again. Well, a life-or-death type pinch, anyway. Not sure she could rely on him to show up to a Sunday dinner on time or… well, to any sort of domestic affair, probably. Not that it would ever matter if the blonde he'd just run after was really his old flame, come back from who knows where. He'd never give Martha a second glance if that turned out to be the case. She shivered a little and crossed her arms around her waist, suddenly feeling strangely chilled and alone.

A flutter that might have been an overcoat caught her eye, and she spun to look, but it was already gone. She decided to head that way to continue her search. She didn't hold out much hope of finding him now, but after all, the alternative was waiting around in the TARDIS for another several hours, alone and anxious and bored out of her mind. Might as well take action and get some exploring in, even if it was only Cardiff.

She kept on until she passed through Caroline Street, a narrow, run-down alley with broken walls, peeling paint, and three or four hole in the wall chippies in a row. At the end, she found a repurposed old brewery with five or six small shops and a piazza in front. A few people were starting to mill about the chip places and other shops for lunch, but none of them sported wildly unruly brown hair and pinstripes. Martha sighed, put her hands on her hips, and slowly surveyed her surroundings, wondering what to do. Then she heard a familiar sound.

Following her ears, she hurried over to the slightly chipped, painted-over glass doors of a bar called the Lava Lounge with a logo depicting blue waves against a yellow backdrop, which wasn't very lava-like in her opinion. Stacks of plastic patio chairs lined the brick wall by the door, and there wasn't any light inside. She leaned her head against the doors to listen.

She heard it again: the familiar whirring of a sonic screwdriver. The sign hanging on the glass said the place was closed until 5:00, but when she tested the doors by tugging on them, she found them unlocked.

Martha opened the door and stepped inside. The lights, it turned out, were on after all. They were just very dim. Other than a fairly nice varnished wood bar sporting rows of bottled wines and liquors at one end of the room, the furniture was pretty rubbish. Most of the scuffed hardwood floor was left open for dancing, and a sad-looking disco ball hung lifelessly from the ceiling. The only seating available consisted of four or five battered yellow and maroon booths with tiny varnished wood tables, and a row of stools at the bar.

The Doctor stood there at the far end of the room in front of one of the little round tables with his back to her, fiddling with some alien-looking equipment. As he heard the door open, he spoke without looking up.

"Rose? Did you get that Argolin mobile neural interface array for the trans-temporal psychic beacon spatio-locator?"

"The what?"

The Doctor quickly turned around and looked at Martha, startled. What on earth was Martha doing here? And more importantly, which Martha was he looking at? His ability to see people's timelines was severely diminished as a human. At this date in 2007, she had probably just left off traveling with him recently. Had she joined UNIT yet?

Of course, knowing himself, it was entirely possible that this Martha was from some other time and had traveled here to 2007 with him in the TARDIS from either the past or the future. He didn't remember ever bringing her here when she traveled with him in the past, but the other him could have picked her up again for a trip or two later on after they separated at Bad Wolf Bay. She didn't look surprised or particularly excited to see him. In fact, she seemed to be waiting rather expectantly for him to say something.

"Er, Martha… Lovely day, isn't it?"

"Charming," she agreed. "Did you find her, then?"

"Find who?" 

"Rose, of course," Martha laughed incredulously. "Was there someone else you've been looking for all this time?"

Ah, thought the Doctor. This must be pre-Crucible Martha, who hadn't seen Rose come back using the dimension cannon yet. She was probably here tracking unusual rift signals for UNIT, and had noticed the energy spike when he and Rose came through from the parallel dimension.

"Can't really talk about that, I'm afraid. Timelines and all that," he answered. "Your future, my past, wibbly-wobbly, you get the picture."

"What's all that about my future? I'm talking about just now, when you ran off without a word to me, shouting 'Rose, Rose,' and chasing a blonde down the street."

The Doctor immediately paled.

"I did _what?_"


	3. Chapter 3

Only a few hundred meters away from the Lava Lounge, at one of the run-down Caroline Street shops that Martha had passed, the younger Doctor and Rose were having chips. They sat at one of three tiny fold-up tables next to the front windows looking out into the alley. The white-painted walls and ceiling were scuffed and unattractively traversed by a couple of power cords and a hanging air duct, but the metal counter and the frying vats looked clean, and the smooth concrete floor had clearly been mopped recently. The only other person in the shop was the manager, a middle-aged man sporting old lady specs and a mullet, who worked on wiping the counter down and otherwise left them alone.

Rose pushed her hair back and popped another chip into her mouth, talking in between bites, while the Doctor ignored the food beside his elbow in favor of leaning his chin on one hand, smiling goofily at her with an almost inebriated expression.

"Well, we've been back together for about a year," she was saying. "I shouldn't really get into specifics, but we've been travelin' like before, saving worlds, fightin' monsters, goin' out fer chips. You know, what'd you call us? The 'Stuff of Legend!'"

"Mutt and Jeff!"

"Shiver and Shake!"

They grinned at each other.

"Are you happy, then? I mean, I suppose Jackie's—"

"She's still with Pete, and they have Tony now. You should just see 'im. He's a little ball of energy. Gets up to more trouble than we do!"

"Did they stay? In Pete's world, I mean?"

"They did, yeah. But it's okay. We got a long time to say our goodbyes. And we – you and me – were already spending most of our time flying around time an' space in the TARDIS. She'd never admit it, but I think my mum finally got used to the idea. Stopped tryin' to talk me out of it, anyway. I left her some tapes and things, before we crossed back over the Void. Messages, like, and gifts. Dropped 'em off in the future to be delivered on special occasions, you know. So at least for them, it'll seem like I'm still around somewhere, far into their futures."

Rose lapsed into momentary silence, and gazed distantly out the window. The Doctor took her hand where it rested on the table and held it in his own.

She turned back to him brightly. "But what about you? You're travelin' with Martha now? I still haven't really got to know her. Met her once, but it was in the middle of a crisis an' all that, you know how it is."

"Oh, Martha's grand. Brilliant, really. Good head on her shoulders. Do you know, when I first met her, her hospital had just been transported to the moon, bang out of nowhere, and do you know the first thing she says to me? She turns and calmly asks 'How come the air isn't getting sucked out?'"

Rose laughed, "That _is_ brilliant. She sounds fantastic."

"Yeah, she is." The Doctor smiled and looked down to fiddle with his drink. After a minute, he added lightly with a nod, "She isn't you, though."

Rose smiled at him silently with her tongue against her upper teeth for a minute, and then impulsively reached across the table and affectionately mussed his hair up into the slightly disheveled just-escaped-a-riot-by-the-skin-of-our-teeth style she'd always found particularly foxy. He still had so far to go, this Doctor. Her hand lingered by his brow, until he took it and linked his fingers through hers.

"Rose… I still haven't… I mean, maybe I have, from your perspective, but from mine…"

She was still smiling at him, adventurous, compassionate, full of humor, and just overall so very _Rose_, that he gave up talking, leaned forward, and kissed her.

She nearly fell backwards in surprise, but caught herself in time. Despite the fact that she'd been frequently snogging, and in fact, shagging, the Doctor _version 2.0_ for quite a while now, she hadn't actually expected it from _this _one.

He pulled away again after a moment, half-lidded eyes meeting her own wide ones. Rose bit her lip, laughed, and pushed her hair back behind her ear awkwardly.

"Is that all right?" he asked.

"Um, 's fine, it's just… I thought you didn't do that sort of thing, 'cos eventually we all 'wither and die' an' you said… well, you couldn't stand watching that, so you never let yourself get too close."

"Oh, I think I can say we passed that point of no return a long time ago," the Doctor answered softly. "The moment Pete caught you at Canary Wharf – no, before that." He sighed and rubbed his hands over his face. "It couldn't have been any harder, Rose, even if we'd…" He still couldn't say it even now, but he was trying. "Y'know, I almost… did some very bad things," he finished lamely.

Rose remembered a pocket dimension containing an alternative universe where one Donna Noble had made all the difference between the Doctor who sat before her now and a Doctor who drowned under the Thames without even bothering to regenerate. She _really_ owed Donna a drink whenever they managed to find her.

"So you…" she faltered, unsure how to ask this without inadvertently telling him about the metacrisis, "You and me could have… been more than just mates, if we'd been together at this point in your timeline? Even though you'll outlive me?"

The Doctor frowned a little. He couldn't have misread the situation, could he? How could any future him _not_ have leapt at a second chance to tell Rose how he felt? "Wait, are you telling me you and he still aren't…"

"Oh, no," Rose interrupted. "We are, it's just… it's a bit different for him. He's… been through some things. Circumstances change, an' all."

The Doctor smiled adoringly at her. "Rose Tyler, no circumstances in the world could change how I feel about you."

He practically glowed with delight. Sometimes, he remembered, everything works out. Sometimes, everybody lives and the hero gets the girl. Sometimes, nobody ends up locked away in a parallel dimension for the rest of her life and nobody else has to spend the next hundred thousand years regretting the one thing he didn't say.

Rose tried to return his smile, but had trouble getting it to reach her eyes. Sometimes, a broken man with a dying friend and an otherwise empty police box turns and walks away.


	4. Chapter 4

Meanwhile, Martha and the other Doctor were hurrying along the piazza back towards Caroline Street. The Doctor knew Rose well enough to guess where she'd go in this area, and if the TARDIS was out of the realm of possibilities (and he didn't think she'd risk that), a nice, harmless chippy was the next most likely spot.

"So you're the Doctor in my future?" Martha asked breathlessly as they ran.

"Something like that," he responded, still glaring straight ahead as if he could almost use his eyes to skewer the stupid past version of himself who was, even now, knowingly putting the entire fabric of space-time at risk for a chance at chips with Rose.

"And you got Rose back? Where am I, then?"

"Went home with your family."

"Is that 'went home with family' the way Rose 'went home with family,' or is that a euphemism for 'whole family got eaten by giant space squid, Martha included?'"

"No, you… Honestly, Martha, you can't ask me about that. You're doing fine, all right?"

"All right." Martha pursed her lips and was silent for a minute. She hadn't imagined herself ever leaving the Doctor by choice, but if he'd suddenly got his girlfriend back, she could see herself not wanting to stay on as a third wheel. Fancying someone who didn't hardly see you past the ghost of his ex was difficult enough already without the ghost coming back again in the flesh.

She nearly ran into him as he pulled up short to avoid being run over by a lorry that was trying to exit the alley.

"All right," she repeated as they caught their breath, waiting impatiently for the intersection to clear enough that they could slip through. "So tell me something that's not about me, then. What's with Rose? I mean, why couldn't you go get her before, but she's back with you now?"

"I couldn't reach her before because she was trapped in a parallel universe," he answered uncomfortably. It was getting easier to talk about it now that he'd had her back for more than a year. It would never be a pleasant topic for him, but he owed it to Martha to give some explanation for all the moodiness and evasive answers his past self had been giving her. She'd gone through endless months of drudgework and old-fashioned bigotry, and even walked across every continent on the earth for his sake by the time she left, and he'd never come close to making up for it.

"And now? What's different now?"

"The walls between universes were weakened for a short while, and travel between them became possible again, briefly."

The street cleared and they broke into a jog again.

"So you went and got her."

"Not exactly, no." He smiled grimly. "I stayed behind on her side. The plan was to make that universe home."

A pang shot through her. She'd thought more than once about the possibility of losing the Doctor to some other woman's affections, or possibly to a tragic but doubtless heroic death, but somehow the thought of the Doctor voluntarily abandoning this universe forever hadn't occurred to her, and in a strange way that hurt worse. She shoved it down, something she was used to doing, and took a breath. "Okay, then what are you doing back here?"

The Doctor took a breath and set his jaw in a determined manner. "We're on a rescue mission. We're here to save a friend."

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**More coming soon! The whole story has already been written, but it needs a little polishing here and there. As beta reader feedback continues to come in, I'll post the next chapters.**

**And speaking of feedback... I would be super happy to get reviews! :)**


	5. Chapter 5

Rose saw her own Doctor (though technically, both felt like her own) coming towards them through the restaurant window and groaned.

"Oh, bollocks." Nothing said temporal paradox like running into your easily preventable half-human clone from the future and learning that he'd go on to steal your girlfriend. Might as well tell him the metacrisis would also commit genocide and then indirectly necessitate the complete mental erasure of his best mate while you were at it.

"Rose," the half-human Doctor said as he came in, trailed by Martha. He glared at his past self, but still nodded a curt greeting before continuing. "We should go."

"Oh, not yet!" The Time Lord Doctor protested in dismay. "Rose!"

Rose had stood up to go with her version of the Doctor, but at the plea from the one sitting at the table, she hesitated.

"Rose." The metacrisis Doctor gave her a meaningful look from behind the Time Lord Doctor and tapped his chest, indicating the one heart.

"I'd… really better go," she said apologetically to the Doctor at the table. She gave his hand a last squeeze, set the Argolin mobile neural interface array on the table before him, and stepped away and through the door that the other Doctor held open. The Time Lord watched her dejectedly.

The metacrisis Doctor turned to Martha. "Martha, it was good seeing you again. Take care." He left the restaurant and caught up with Rose in the street.

The Doctor watched her go helplessly, and Martha watched him in resignation. So that was their future. She'd already grown to suspect it, but it was still disconcerting to see definite proof that she'd never stand a chance with him the way she wanted. She thought about telling him off for letting her go on so long hoping, but the look of grief on his face held her back.

She sighed and crossed her arms. It was frustrating as hell, but she loved the poor alien sod enough not to want to see him miserable, even if they were only ever fated to be best mates.

"You could go after her, you know."

"I can't," he said softly, still gazing after them through the window glass with a carefully blank look. Martha could almost hear the familiar old emotional shutters banging closed.

"What, 'cos she already has you? 'Cos she's from the future? Seems to me that cat's already out of the bag. So you know you won't see her for a while. Cheer up! At least you'll see her again. That's something you didn't think would happen before now, right?"

He swallowed numbly, still staring through the windowpane after them.

"So go on," Martha insisted. "Go give her a proper goodbye! I guarantee she doesn't want her last sight of past-you to be you sulking with your big doe eyes in a chippy. You could at least see her off properly, and have a nice memory to hold onto til you see her again."

The Doctor looked back at her indecisively. She rolled her eyes and nodded toward the door. Honestly! The most brilliant scientific genius in the universe, and he couldn't be half thick sometimes about relationships.

A slow smile spread over his face, and he bounded up, gave Martha a peck on the cheek and ran outside. Martha smiled ruefully, shook her head, and followed him.

It took only a minute to make up the distance to the couple ahead of them, and the Doctor slowed down to an artfully disinterested swagger a short distance behind them with his hands in his coat pockets. Feigning nonchalance, he loudly called, "So, I don't really see the need to rush off quite yet. We could hang around a bit more. I could even help with that psychic energy scanner you appear to be building."

Martha fastened a determined smile on her face, loyal to the last, and helpfully chimed in: "I bet it goes faster with four sets of hands. You did say you were on a rescue mission."

"Sometimes a little help makes all the difference," Her Doctor added, grinning approvingly at her.

The metacrisis Doctor looked back over his shoulder at them with one eyebrow raised in surprised annoyance. "What would you know about it? And what are you following us for? Now sod off." Beside him, Rose kept walking but broke into a silent grin. It was nice to see his past self bounce back, even if it did put their entire timeline in jeopardy.

"I know you need an Argolin mobile neural interface array to get it working, and I happen to have one here. Would be a shame if I dropped it." The earlier Doctor tossed it and caught in one hand while making a pretense of grave concern at the possibility. "Imagine, I drop it here, you go back to your TARDIS and find yours in pieces. Naturally you'd have forgotten ever breaking it, since I'd have wiped my memories after this whole little run-in."

"This is extortion!" the metacrisis Doctor cried indignantly, stopping to face his earlier self. He and Rose were using their own newly acquired parts, not future versions of what the other one was carrying, so the threat wasn't actually very effective, but still – it was the principle of the thing.

"Only you would try to blackmail yourself," quipped Rose, enjoying this entire fiasco far too much. She whacked her current Doctor on the back in unbridled mirth.

"What do you even want?" he demanded of himself, glancing askance at the blonde beside him with an air of long suffering. The younger alien marched up close to the elder with a smile.

"I just want one more adventure with Rose, just to tide me over until we meet again. You can even stick around to make sure I mind my manners and lock up my memories properly in the end. That's it."

"You're insane," the half-human Doctor replied, eyes widening in incredulity.

"You would know. You were me."

"You won't even remember it. What's the point?"

"_You'll _remember it. And I want a chance to say a proper goodbye. We didn't get to, last time. You remember."

That was a low blow. He did remember, staring unseeing into the empty space in the console room where only moments before had stood her image, broadcast from Bad Wolf Bay – feeling wetness on his cheek and the numb surprise that he still had tears left after the loss of Gallifrey.

"You won't be able to handle it," he stepped forward and whispered severely to his previous self, keeping his voice low so the others wouldn't hear. "I know what you're thinking, I know where you're at emotionally right now, and you could screw up the entire timeline."

"I won't!"

"I know you won't, but only because you're not getting the chance. Now go away!" He turned and stalked off purposefully in the direction of the pub.

Rose had been finding all this very amusing, but her smile faltered as she watched her current Doctor storm angrily away from the other one. As the metacrisis Doctor marched back past Rose, he took her hand and pulled her along with him toward the Lava Lounge.

"Doctor, wait, what did you say to him? Doctor!" she protested quietly, increasingly curious as she glanced between the one holding her hand and over her shoulder at the one behind them.

"There's no trusting that lunatic," he fumed irritably.

"You're not getting rid of me that easily," the other called after them, blithely following behind.


	6. Chapter 6

Rose and the metacrisis Doctor stepped into the empty bar, arguing with each other in hushed whispers as Martha and the Time Lord Doctor followed not far behind.

"He's already got to wipe his memory anyway. How much harm can it do?" Rose was saying.

"You have altogether too much faith in our capacity for self-sacrifice. If he finds out I'm not him – well, not physically him, anyway – and he learns what my existence will cost him and Donna, do you really suppose he's going to take that quietly? He could decide time is in flux and go out of his way to alter the future!"

"_Is_ time in flux?" she asked, curious.

"Does it really matter? I'm an anomaly, Rose; I don't think it's going to much bother him to wipe me out of existence. I shouldn't have existed in the first place."

"Don't say that!" she admonished. "And anyway, he hasn't noticed you're human yet. I don't think he can even tell the difference."

"Do we really want to take that risk? Look, he won't remember it, so letting him stay isn't going to ease things for him any once he leaves. And he's not that far away from picking up Donna, which will help him a lot. You don't have to feel sorry for him." He was leaving out the rapidly approaching year from hell, in which he would spend twelve months locked in a birdcage in the form of a gnome while Martha wandered the earth, dodging the Toclafane and shouldering the burden of saving the entire world all by herself. He didn't think it would help his argument any.

"Yeah, he'll pick up Donna, and then he'll lose her, and be all alone again. An' when he unlocks his memories again at that point, I want him to know that you an' me did all right, an' that he's still loved." Rose had set her jaw like she did when she'd made her mind up to do something, and the Doctor knew he wasn't going to be able to talk her out of this.

"I'm not budgin' on this," she added as if reading his thoughts. "You may not care if you end up with one extra memory of eatin' chips in Cardiff with me, but for th' other one, this is my last chance to say goodbye."

While the Doctor tried to work out some sort of response to convince her otherwise, his Time Lord counterpart had been giving them some space. He was pretty sure Rose was on his side, so he would let her do the talking. Meanwhile, he'd been poking around the pile of half-assembled alien gadgetry on the table with growing interest, and now he held up the larger piece of what had been built so far and turned to interrupt the domestic duo.

"A trans-temporal psychic beacon spatio-locator! Why would you be building one of these?"

The metacrisis Doctor reluctantly turned and answered with an exasperated sigh. "To trace a psychic distress call, obviously."

"A psychic distress call that transcends time? There's no species left in the universe that can send one of those. Look at this. You don't even know what year you're aiming for."

The half-human Doctor stepped forward and irritatedly pulled the device out of his predecessor's hands. "I've a very good idea of who and when I'm aiming for, and I'm just trying to get the date precisely right. And I'll thank you not to stick your nose in your own future affairs!"

"Then why aren't you using the enhanced artron emitter?"

"I haven't got one."

"Why haven't you got one? We always carry a spare aboard the TARDIS."

"It doesn't matter why. I'll manage with auxiliary flux circuit."

"Oh, that'll never work. Tell you what – you loan me Rose for a bit, I'll loan you Martha, and I'll throw in my artron emitter so you can get your locator working."

"Oi!" Martha interjected, slightly insulted. So much for taking the moral high road and trying to help him.

"You can keep Martha, and your emitter! No offense, Martha," the future Doctor added as an aside before continuing, "I don't need it. I'll just re-route the main space time element and synthesize a dynamorphic matrix."

"You can't re-route the main space time element, you'll blow up the orbital phase conduit!"

"Just let 'im stay an' help," Rose interrupted, fed up with the arguing. "You've already admitted you run into yourself all the time. An' you can't convince me hewould be so eager to stick around if reapers were really a threat."

"You trust him over me?" Rose's Doctor looked offended.

"He _is _you!"

"Now this is just getting weird," Martha muttered to herself.

"He could learn _things _about his_ future, _Rose," the Doctor hissed as quietly as he could manage, glancing at Martha and his predecessor out of the corner of his eye, obviously trying to avoid revealing specifics.

"Not if he's _with me,_" she argued back in the same low voice. "I'll go back to the TARDIS with him to get the part, we'll drop it off here and I'll keep 'im out of your way until the thing's ready! You don't need my help with it anyway."

"I'm not sending you off into his TARDIS, alone with him!" the Doctor squeaked, his voice going up an octave in alarm.

"Oh, will you relax, already! It's not like he could take off with me on board. It'd cause a paradox!"

The Doctor just raised his eyebrows and gave her a significant look.

"Oh, you can't be serious!" she laughed. "He isn't _mental._" When the Doctor still didn't say anything, her grin faded a bit. "He wouldn't, though. You wouldn't've. You said, back on the beach, that you couldn't come through because it would destroy both universes. You wouldn't do it."

"Let's just say it's a good thing Donna showed up when she did," he answered dryly.

Rose's eyes widened, and while she processed that unnerving bit of information, he turned back to the younger him and Martha, who were by now sitting on barstools, swinging their legs and awaiting the verdict with all the patience in the world.

He sighed. "I'm not leaving you alone with Rose," he finally said firmly.

"Oh, obviously," the earlier one replied.

"You're a menace."

"Says the kettle to the… kettle." He looked round at Martha with a cheeky grin. "Kettle, as in pots and kettles…? Yeah? No?" She shrugged.

"You help me build this thing, we all go out for dinner after. All four of us together. You can talk to Rose a bit, staying well in sight. And then that's it. You forget this ever happened, and Rose and I leave. Martha?"

"Yeah?"

"We'll have to adjust your memories, too. I'm sorry."

She stilled her legs for moment, then shrugged again. "As long as you don't touch anything I need for my exams, that's okay. I trust you."

Both Doctors winced a little, one remembering similar words of trust on Martha's lips as she floated toward a homicidal sun in a jettisoned escape pod, the other remembering a ginger-haired super-temp who had _not_ responded to a similar proposal in the same way.

"All right," the Time Lord said finally, hopping down off his bar stool and clapping his hands together. "Let's get started."


	7. Chapter 7

A little while later, Martha and Rose found themselves with their chins resting in their hands, elbows on the table, eyes glazed over in boredom as the Doctors argued about some incomprehensible technical detail in the background.

"The temporal harmonics coupling can handle more than that if we magnetize the linear tetryon generator."

They'd been going on like that for about an hour. Rose eyed a dartboard speculatively and considered taking a few alien potshots for practice. It had been a while since Torchwood. She wouldn't want her aim to get rusty.

Meanwhile, Martha made good use of the opportunity to finally make her own assessment of the woman who had so enchanted the Doctor, and so far, she didn't seem all that impressive. The constantly referenced 'Rose' had supermarket blonde hair that clashed with her brows and was badly in need of a touch-up at the roots. She wore a wrinkled gray tee over a snug pair of jeans, her make-up and hoop earrings were a little on the chavvy side, and it was obvious that she couldn't follow the technical conversation any better than Martha. She didn't look particularly well educated, either. In fact, having heard her speak, Martha was almost certain she came out ahead of her rival on that front. It was a little depressing to have lost out to this.

Rose looked up from the chewed nails she'd been inspecting, met Martha's eyes, and smiled. "Darts?"

Martha smiled back politely, hiding her begrudging thoughts with the skill of one who has spent many years as the lone family mediator in the middle of a nasty divorce. "Okay."

They played a few rounds until the argument in the background bubbled over into un-ignorable territory.

"You can't use a temporal harmonics coupling to simulate an asymmetrical inversion field without a nucleonic frequency stream emitter!"

"Oh for heaven's sake," Martha cried. "If he needs a whatever-it-is and we have one in our TARDIS, why don't we just give him that, too? Maybe the reason he's missing all these parts in the future is that we already gave them away here in the past."

The Time Lord spun around and beamed at her proudly. "Oo, Martha! Good deduction!"

Rose and the metacrisis shared a brief troubled look. They couldn't very well tell the other two, but the actual reason their resources were so slim was that their TARDIS was less than a year old. The only gadgets she had on board were the ones they'd managed to scrounge out of Torchwood storage or pick up on the short list of planets they'd had time to visit in the parallel universe before getting the distress call and packing up to cross back over here.

"All right," the metacrisis finally sighed. "I guess we haven't got any other options. We'd best get busy then. You girls go dig up the part, and myself and I here will finish up the rift calibrations and then meet you in the TARDIS. I figure we have, oh, only about an hour left in the pub before the staff start coming in, anyway."

The Time Lord looked up and opened his mouth to protest the departure of Rose, who was the whole reason he'd tagged along in the first place, but his later counterpart shoved the half-finished device into his hands and hit the 'on' button, diverting his attention again with the appearance of a loud grinding vibration that definitely shouldn't be there. The two Doctors shared an identical grimace.

"Right," Rose nodded briskly. "We're off to get the parts, then. Meet you in the console room, yeah?" She hopped down from the stool and threw an arm around Martha. "After you! It's your TARDIS."

Martha blinked in surprise, and as soon as they'd left the pub and started walking down the street, she had to ask, "It doesn't bother you?"

"What doesn't?"

"That there's a… a '_my TARDIS'_?"

Rose looked amused by the question. "Well, you're the companion in residence, right? Your TARDIS, my TARDIS, your Doctor, my Doctor… I reckon that's the easiest way to keep them sorted."

"Yeah. I just… Nevermind."

"What?"

"I guess I thought you'd be a little, I dunno, miffed to find someone had taken your place while you were gone. As a companion, I mean. But then I guess you know where you stand with him."

Rose considered the woman next to her for a minute before she answered. She knew from conversations with the Doctor during their time in Pete's world that his companion Martha had fancied him for a while. This whole encounter couldn't be fun for her.

"Weeelll," Rose answered slowly, choosing her words carefully. "I did get a bit jealous when I first met Sarah Jane, one of his old companions. And I was a bit put out the first time I saw you talkin' to him, too – we were all on the video chat an' he couldn't hear or see me. Tech problems. Hasn't happened yet, for you," she said by way of explanation. "But then later, when we did meet, I was…" she trailed off, "er, well… we saw a bit of action, is all, so all that pettiness got to seem a bit silly, really."

"But at that time, were you and he already…? I'm sorry, it's none of my business."

"We were… best mates." Rose grimaced. "Your Doctor still hasn't… he's got this line he never crosses with companions."

"Except by your time, he has."

"Errrrr… it's complicated."

She didn't want to give off the impression that the Doctor was available – even leaving her own feelings aside, it wouldn't be fair to get Martha's hopes up like that. But she also balked at saying he and she were an item when she remembered that, after today, Martha was more likely to run into the _other_ future Doctor than her own metacrisis one, and the _other _one was almost definitely still following the same old rules as usual.

Oh well, Martha would figure things out eventually. They'd all get to meet the duplicate Doctor when they towed the Earth back after the Crucible.

She fell silent for a bit, thinking about the other Doctor and what would've been if he had just ducked that Dalek ray.

"Anyway, 's like… even if we just stayed best mates an' all, I'd still want to keep traveling with him. It's easy to fall for him, even when you know he can't reciprocate. It doesn't mean he doesn't care. It's just that he lives such a long time. It took me a while, when I first started traveling with him, but eventually, I guess I just realized it didn't matter if we ever… you know. I knew how I felt, regardless, and I would have stayed forever."

Rose smiled at a memory of an alien orange sky and flying stingray creatures, but then she caught Martha furrowing her brow over the puzzling "would have." Realizing what she'd said, and she quickly threw Martha another bright smile.

"Anyway, you know how he is. He cares about everyone, an' he'd risk his life for anyone. That's what makes him so amazing. If he didn't do that, if he didn't always try to save everyone, he wouldn't be the Doctor, yeah?" She smiled at Martha companionably. "So there's no point in me getting jealous of his other companions. As long as I've got him, and he's got me… That's what matters."

Martha gave her a little smile back and together, they lapsed into an awkward silence. It hadn't been all that easy for Rose either, then. She realized she felt a little ashamed of how she'd sized up the other girl earlier in the pub, and decided a change of subject was in order.

"So, um…" Martha began uncomfortably, breaking the slight tension that had developed between them. "I hear you've been to New Earth?"

Rose broke into a welcome peal of laughter. "Oh, that was a lark! I got possessed an' everything. Plus we ended up saving about a thousand people from being human lab rats for a bunch of evil cats. How did your visit go?"

Martha, seeing an opportunity to get back on the right footing, quickly launched into her own story. "Well, he'd promised me a trip to see the future, and ended up taking me to a slum in the middle of a rainstorm, for one thing."

"Let me guess – Not what you'd had in mind!"

"Not a chance! And I was only there about half a minute before I was drugged and kidnapped…"

The two swapped stories of their adventures the rest of the way to the TARDIS, and by the time they entered the ship, they'd come to a better understanding of each other.

As they entered the console room, Martha sighed and came to a stop in front of the time rotor with her arms crossed.

"I've got to admit, I really don't have the slightest idea what we're looking for, or where to find it if I did. This place is enormous. Did you know he's got a entire skating rink in one room?"

Rose laughed. "No, but I did run across a room with nothing in it but about four billion boxes of jelly babies. I don't even think he eats jelly babies."

She walked up to the console and tapped a few buttons. "Anyway, we just need to use the TARDIS internal navigation app. The old girl will tell us where to go." Rose pulled it up on the console screen like an old pro.

Martha pondered something aloud while her new friend worked. "What did the Doctor need to work in the pub for, anyway? Doesn't he usually do his tinkering in the TARDIS?"

Focused on the console, Rose answered distractedly, "Oh, probably 'cos the temporal energy fluctuations coming off the rift are too unreliable everywhere else. Different timelines crash into each other here in Cardiff, so it's the best spot for doing a trans-temporal search 'cos it'll give you the best range, but you have to be careful 'cos the fluctuations will mess up your instruments unless you get the calibration just right, and the best place to do that is the place where the two farthestmost reaches into the past and future intersect, which just happens to be in the center of that pub."

She turned to see Martha staring at her open-mouthed, and realized what she'd just said was a bit impressive. Unable to help herself, she gave Martha a teasing smirk with her tongue between her teeth. "Torchwood. Worked there for a bit in th' other universe. You get to know the rift pretty well," she explained. "Well, I've got the locator, so let's get on, then."

Following a map on a little reader gadget that the TARDIS had ejected for them, the girls traveled one flight down the spiral staircase, along a corridor, took two lefts and a right, and ended up in a small room with a cupboard. The little not-actually-a-GPS gadget blinked a picture of the cupboard at them, so they opened it and found a single likely looking device inside. Rose took it and handed it to Martha.

"Right, then! I guess that's it. Time to head back."


	8. Chapter 8

When the girls finally attained the console room at the top of the stair again, they found the Doctors already there, hooking the newly minted trans-temporal psychic beacon spatio-locator up to the TARDIS computers. It looked rather like a metal erector set scaffolded into the shape of a giant bike helmet, with some blinking lights on top. Once strapped to the user's head, it would provide a telepathic interface allowing the user to trace the source of any telepathic message being sent to him/her across the five dimensions of time and space.

Martha handed her Doctor the nucleonic frequency stream emitter and followed Rose into the kitchen. "We're going to put the kettle on, so give us a shout if you get it working," she waved as she disappeared around the corner.

The Doctor passed the part to his future self and settled in to watch as he carefully set it into its slot in the headpiece and started sonicking the connections together. While wiring the locator into the console, the Time Lord had gotten a glance at some unusual rift readings the TARDIS had noted earlier. Now, with Rose and Martha out of earshot, he asked his counterpart about it in a quiet voice.

"How _did_ you get back across the Void?"

"You know I won't answer that. Why even bother asking?"

"The TARDIS recorded you coming through – or the energy spike that accompanied you, at any rate. You practically landed on top of us at the same time we did, and you came straight from Pete's world. And from what I can see, you just barged straight through the brute force way, which means I must never figure out a way to cross the sealed Void, or you would've taken that instead."

The half-human Doctor was silent, gazing at the device in his hands without actually focusing on it.

"And the brute force way shouldn't even be possible," the first continued, "unless the walls between worlds have become dangerously thin. If I checked the barrier now—"

"You'd find almost no barrier at all," the other Doctor finished for him. He closed his eyes unhappily. "The walls have been weakened again."

"By what?" When the other didn't answer, he added, "Not by _us_?" The earlier Doctor tried to chuckle at the suggestion that he would ever do anything as daft as doom two entire universes just to get Rose back, but the laugh somehow died in his throat. He couldn't quite convince himself that it was out of the realm of possibility.

"No," the other replied. "Something is coming." His eyes grew distant. "Time is bleeding. Shapes of things once lost are moving through the veil." He shook himself and then met the other Doctor's eyes as if coming out of a dream. "I don't know what it means. My other – that is, the future 'us' is already involved in it in some way, and I don't know the details. I only got the bits of images, words and phrases that came through the psychic link with my friend. She's stuck right in the middle of it, and whatever it is that's weakened the barriers, it's triggered a complete neurological implosion process. If we don't find her before it reaches the critical stage… Well, that's why we're working to pinpoint the space-time coordinates so precisely."

"Hold on, you mean the distress call you're tracing now is coming from the middle of a space-time event _we're already involved in_?" The Time Lord's eyes grew wide in alarm. "You're not saying…? You don't mean to intentionally meddle with our own timeline? Have you completely lost your mind? You'll set off the Blinovitch Limitation effect, trigger a paradox, get eaten by reapers and take the rest of the universe with you!"

The half-human, half-Gallifreyan glowered at him defensively. "And what do you think you're doing right now? At least I have a real emergency to deal with. I'm not crossing timelines for a lark and a plate of chips!"

"Rose is not some lark! Of all people, _you _should…" his voice wavered a little and he turned away from his other self to face the time rotor, eyes hard. It was maddening to be so jealous of the person you would later become. The idiot didn't even seem to appreciate what he had!

The metacrisis watched him for a moment, expression softening. "Look," he began solemnly, "Donna Noble – our friend – is about to die a gruesome death far before her time, and it's all our fault. I know you don't know this yet – you've only met her the once – but she is going to become so important, so very important, to you and to the universe. Future 'us' isn't stopping it, whenever it is, and I don't know why he can't, but I do know that if there's anything I can do, anything at all, I have to try."

The other Doctor looked sideways at him, still appalled at the idea of deliberately crossing his own timeline to interfere with events. "If Rose knew what you were attempting—"

"Rose knows; she understands. She came with me to help. She left her family and everything behind in Pete's world, and if we succeed in rebuilding the walls between worlds, she knows she'll never be able to go back. And it's not like I didn't want…" He caught himself before he could finish the sentence.

He didn't want to say so out loud, especially to his younger self, but it had hurt to give up his own tentative hopes of making a home in the parallel universe. During the year they'd lived in Pete's world, he'd been inexplicably (but wonderfully) welcomed into Jackie's growing family of mismatched parallel-world swap-outs, and being human, he'd thought he might finally have a chance to grow into a family that he could experience the slow path with, even if he and Rose had continued using the new TARDIS every chance they got. They'd still gone on adventures, only now Jackie's place had become a sort of home base to return to in between trips to Xelnor 5 and the seventeenth century. It had been the first time since Gallifrey that the Doctor had even had a place to return home to.

"At any rate," he cleared his throat, "if _he_ doesn't manage it, it's all a moot point anyway." He didn't need to explain to himself what would happen if their future self didn't succeed in repairing the walls.

After watching the carefully controlled emotion on the face of his later counterpart, the Time Lord Doctor relaxed a little. He didn't know everything that was going on, but he knew himself well enough to know when he could be trusted and when he couldn't. This him hadn't gone mad, not yet anyway. Crossing one's own timeline was immensely risky, but there were ways to mitigate the risk. If they were careful, it could be done.

He nodded wordlessly to the other, acknowledging that he would help in as much as he could, and they got back to work.


	9. Chapter 9

**Slightly longer chapter this time! **

* * *

Rose and Martha returned to the console room with the tea just as the Doctors were finishing up the chin-straps on the thing they'd created. It looked like a sci-fi B-movie prop, with little blinky bits on top and piles of wires running out of the left side into the TARDIS computers.

The half-human Doctor was sitting in a hard reclinable chair the TARDIS had helpfully provided, holding the device aloft in front of him while the other Doctor secured the last latch. Finished with the strap, the metacrisis brought the helmet-like contraption down on his head and fastened it under his chin.

"All right, I think we're ready to give this a go," the Time Lord said as the metacrisis settled back into his seat. "Powering on the time differential dampeners."

"What's he doing?" Martha asked, coming up behind her Doctor with two cups of tea. He accepted one gratefully from her as she watched his later self sit back under the helmet with his eyes closed and his hands gripping the armrests of his chair. Rose settled down on the jump seat with her own tea to watch from the side.

"He's got to sink into a telepathic trance, and follow the distress call back from where his own brain's receiving it to its point of origin. The TARDIS will record the data from the psychic spatio-locator and display it on the screen as a set of space-time coordinates. That'll help us pinpoint the exact month, day, and hour that the distress call came from, so we can pop in, fix whatever needs fixing, and pop back out while doing as little damage to the timeline and established events as possible. If we're _really_ lucky, we won't run into a third version of us from _that _timeline, we'll avoid a paradox, and the universe won't collapse in on itself, killing us all."

"I'm holding the connection," the metacrisis Doctor said, eyes still closed under the helmet. "It doesn't seem to be oscillating at all, which indicates that from her side, this is still part of the initial communiqué – no more energy bursts since the first. Luckily, she linked to me where I match her subjective linear timeline, regardless of what objective era I'm traveling in, so I've been able to keep the telepathic signal stable regardless of the time differential. Clever, Donna!" He raised his eyebrows in an impressed way. "'Course, she'd know I'd be harder to find if she sent a message straight across the Void to her parallel point chronologically. Time moves at a different speed in Pete's world. Well, that and the fact that she herself gave me the idea to prevent being marooned on Earth by shatterfrying the—" He remembered where he was and swallowed the rest of that sentence before the words 'plasmic shell of the coral for the replacement TARDIS' could slip out. "Errrrm, anyway, she knew I'd probably be traveling through time," he finished lamely. "Okay. Taking up the line now, going to follow it back. Should take about two minutes." He lapsed into silence.

"How'd he get this 'psychic message,' then?" Martha whispered to her own Doctor, not wanting to interrupt the other's concentration.

"Apparently he got blasted with it while traveling in Pete's world – that's the parallel universe. Managed to lock on and create his own connection from his end before the energy burst from his friend ran out. Donna Noble, he says! Having met the woman, I'm not sure I can believe him. Still, I've seen crazier things in the universe," he shrugged.

"But you said before that a psychic… trans-temporal whatever was impossible."

"It is, or it should be now, at any rate. Only a Time Lord could send out a psychic signal that exists outside of time." He swallowed and paused, his face taking on a distant, half-sad, half-nostalgic look as it usually did when something reminded him of Gallifrey. "My people used it to connect to the Matrix – a sort of supercomputer micro-universe that held information about the past and future. We needed an apparatus rather like that one there to do it," he tilted his chin to indicate the tinker-toy helmet perched on his duplicate's head. "It's also the same ability that allows me to sense other Time Lords, whether or not we're existing in different eras. And I'm not sensing anyone, which leads me to believe the reception of this particular signal is limited to one Time Lord and one point in his timeline alone. Which, incidentally, is also impossible."

"So how is this Donna able to do it?"

"That, Martha, is the million credit question."

The second Doctor, who'd been quiet up to now, suddenly let out a strangled cry and bent forward, teeth clenched in pain. Rose leapt up from the jump seat and knelt beside him on the left, taking his hand for moral support.

"Doctor!"

"I'm all right, I… ughh… just found her, and she's channeling a lot of pain. I can tamp down on it, give me a sec…"

He slammed his free arm against the armrest as his back arched in a sudden convulsion, and Martha instinctively moved to hold his free hand to keep him from hurting himself. Her medical training urged her to clear the device from around his head and lower him to the floor before he went into a full seizure, but she didn't dare risk removing it while he was still telepathically connected, and surely her own Doctor would step in if it were truly necessary. She glanced back at him in apprehension, but he merely watched stoically as his counterpart flailed.

Abruptly, the convulsions stopped and the future Doctor slumped forward, breathing heavily. The lights on the helmet blinked off and the whole thing hissed mechanically as it retracted from his head and over the back of the chair. Rose and Martha kept their grip on each of his hands. He looked up at them and then at his younger self with the flush of triumph on his face.

"Got her! She's in 2009, Christmas Day, 3:00 P.M., Chiswick, right outside her house!"

"Yes!"

"Fantastic!"

"Well done, if I do say so myself."

The warm cheer of success filled the room and all four of them began to talk at once. Then Martha asked an idle question and the room fell silent.

"Doctor? Do you have a fever?"

The metacrisis Doctor and Rose both stared at her in dismay. Martha smiled uncomfortably, perplexed by their reaction. "I'm sure it's nothing. It's just, you feel a little warm. Usually you run more on the cool side by human standards."

"No, no no, not at all, I'm fine," the human Doctor grinned at her, quickly recovering from his initial reaction. "Just a little heat stress from the telepathy, that's all."

The Time Lord, who had been busily inspecting a monitor at the console, frowned and turned to look at his duplicate. He hadn't actually been listening, but his future self was backpedaling away from whatever Martha had said, and that drew his attention. He, better than anyone, could tell when he was trying to hide something.

Intrigued, he walked over and took the hand Martha had just released. The metacrisis forced himself to resist the urge to pull away, which he knew would only make his counterpart suspicious. Instead, he yammered on with forced cheer.

"Oh, ahh, right, now that you mention it, I was feeling a little woozy earlier, wasn't I, Rose?"

"Yes! Right," Rose hurried to agree, suddenly over her own speechlessness. "You even had a bit of a tickle in your throat, you said."

"Must have caught something on Ralafea. We were just there the other day."

"That's right! In fact, I remember seeing a bloke cough behind you in line for the fried geeblerasts. Right on your food, even."

"This isn't a fever," said the younger Doctor. "This isn't right at all. 98 degrees Fahrenheit, excreting cortisol, epinephrine, a mix of sodium, potassium… What is this, perspiration?" He shook his head disbelievingly and adjusted his fingers on the other's wrist to feel for a pulse.

Left with no other options, the half-human Doctor finally did yank his hand away and tried to rise.

"All right, that's enough of that," he sputtered, "I really have a very hale and hearty constitution, and I don't need you coddling me like some—"

"If you're so hale and hearty, what are you doing excreting _human_ stress hormones?" accused the other Doctor. A brief scuffle ensued in which the human Doctor tried to rise from the chair, the Time Lord pushed him back down, and the human Doctor couldn't get his legs under him enough to shove the other off him. They struggled for a moment. The Time Lord used one knee to pin the other's left wrist, caught the right with his left hand, and pressed his right hand against the other's chest and held it there just under the blue suit jacket. There was a moment of stillness and both Doctors held their positions, one pinned helplessly, the other determined to uncover the truth behind his duplicate's strange behavior.

Then, abruptly, the Time Lord leapt back off his duplicate and fell back against the console.

"…No."

Rose started toward him regretfully. "Doctor—"

"What is it?" Martha asked in bewilderment.

"You're not me!" the Doctor accused the metacrisis. Then he turned to Rose. "And you – are you—? We're not—?" He looked between the two of them.

"Doctor, let me explain…" Rose reached out to him.

"You said we'd be…" He stumbled backward around the console to evade her and ended up hitting the jump seat with the backs of his knees, and fell into a sitting position. He opened his mouth and closed it again, watching the metaphorical dismantling of all the sudden hope he'd allowed himself to feel for the last couple of hours. Mentally kicking himself for being so eager to believe, he dropped his head into his hands. "This is impossible. How could he – Who is he? _What _is he?"

Martha fumed. "Will someone please tell me what's going on?"

"I've got one heart, that's what he's going on about." The metacrisis Doctor grimly answered as he finally freed himself from the contraption in the chair and stood up, his hair mussed from the scuffle. "And we can't discuss it anymore. This conversation has to end here, and you've both got to forget any of this ever happened. We've already gone too far, and the timelines are in danger at this rate."

The full Time Lord scoffed contemptuously from the jump seat without looking up. "What danger? Paradox? You're clearly not any future version of me, so I think that excuse has worn a little thin." He lifted his head and turned to Rose again, eyes bitter and resentful. "And are you even real, or are you some kind of… of copy, like him?"

Rose's mouth opened in shock, which quickly changed into indignation.

"'Course I'm real!" she retorted, angry at the implication of malicious deception on their part. "An' he's real, too! He's as much _you_ as you are! How can you even say something like that?"

She sounded exactly like Jackie that time he'd accidentally brought her home a year late. The Doctor flinched involuntarily.

"And you're one to talk, Mr. Oh-by-the-way-I-just-changed-my-face-and-voice-and-everything-about-myself-but-it's-still-me? What was it you said when you regenerated? That I gave up on you? An' you never even warned me you could do that, that one day you might just explode into a ball of light and suddenly look and act completely different?"

She marched up to him, putting herself protectively between the metacrisis and the _other _one. The Doctor found himself leaning away into the back of the jump seat with a wince. He was starting to feel distinctly less sure of his moral high ground.

"At least he acts the same!" she continued angrily. "Speaks the same, looks the same – _kisses _the same! Don't you tell me he's not you! He is every _bit _you! Do you really think I'd have left you for him if he weren't?" Her eyes welled up and she abruptly shut her mouth to just glare at him instead.

Behind her, the half-human metacrisis scratched the back of his neck awkwardly, trying not to look slightly pleased. The earlier him hadn't been supposed to know about _that _either, but let him chew on that for a while. She'd had a choice on that beach, and she had chosen _him._

Meanwhile, the younger Time Lord had somehow managed to wilt even further under her stare and raised his own hand to rub the back of his neck uncomfortably, unconsciously mimicking his duplicate against the console.

"All right, all right… he's real. I don't understand it, but I believe you."

Rose huffed a little and went back to hold her own Doctor's hand, still incensed.

Martha was horribly confused.

"Wait, now hold on," she said to the metacrisis Doctor. "So you're human again? Does that mean you used the Chameleon Arch? Are you in hiding again?"

"No," both Doctors answered at the same time, and winced. The Time Lord Doctor, keen to redirect attention away from his initial reaction, took over the rest of the explanation. "He can't have gone through the Chameleon Arch to get like this. He's got all my memories, he's telepathic, and he thinks like me. That wouldn't be possible if he were a normal human. The telepathy, he could _maybe _keep_, _on a weaker scale, but I had to store my memories and my consciousness in the fobwatch the last time, remember? I had a human brain, and the human brain isn't biologically capable of containing a Time Lord consciousness. I'd have burned up."

His half-human counterpart nodded and looked somber. "That's exactly the problem, actually."

Rose, having cooled down a bit, put an arm around him supportively. He smiled gratefully at her in response before explaining.

"I was… an accident," he said with a sigh. "You – the real future you, that is – got grazed by a Dalek death ray in a stupid moment of inattention, and having just found Rose again, I – sorry, _you_, to be strictly accurate – tried to stave off regeneration by venting the excess healing energy into your disembodied hand."

"My _what_?"

"The one you lost to the Sycorax. Jack had it. It's a long story… Anyway, it's my hand now. Here it is." He held up his right hand and wiggled the fingers.

"Are you telling me you _grew _from my amputated limb and… and somehow turned into this half-human hybrid?"

"With a little help from Donna, yes."

"That's why he has this psychic connection with her," Rose explained. "They're still linked somehow."

"A human-Time Lord biological metacrisis…" the earlier Doctor muttered to himself in dawning comprehension, eyes wide.

"A two-way metacrisis," his duplicate corrected. "Donna caught the telepathic feedback from my generation, and all of our knowledge and abilities copied over to her."

"And Donna's just a regular human…"

"…with a regular human brain." The Doctors were both silent for a moment, eyes drifting to the floor as they contemplated the inevitable result.

"So what happened to this Donna?" Martha finally interjected. "I mean, you must have figured something out to save her, or she wouldn't be around to need rescuing now."

The human Doctor looked reluctant to answer, so Rose spoke for him. "We assume he erased her memories," she said. "Every memory of him, the TARDIS, and everything that had happened since they met."

"It would have been the only way to save her," the Time Lord agreed aloud, already running through the possible options in his head.

"No," the human metacrisis immediately contradicted, looking up from the floor to meet the eyes of his mirror image. The Time Lord was startled to see a spark of anger there. "That wasn't why we did it."

It had been hard for the human Doctor to bite back the bitterness he felt on Donna's behalf. If there was one difference between him and the Time Lord he'd sprung from (other than the absence of certain major internal organs), this was it. The metacrisis had left traces of himself in Donna's head, and she'd done the same in his. The Time Lord had suspected how Donna would react. The metacrisis _knew. _He _knew_ that Donna would rather have died than lose who she'd become and go back to the way she was before she met the Doctor. He'd heard her begging and pleading with him through their active link clear across the Void when the memory wipe came. He could practically still feel her screaming in his head now, aching to be set free from the memory lock that was keeping her alive.

"We did it to save ourselves. Because we couldn't handle the guilt," he explained acidly. "We couldn't bear to let one more friend die doing what should have been _our _job."

The other Doctor stared at him in dismay. "What else could we have done?"

"I don't know. But there has to be another way."

"Even if there were, surely it's too late now. You've – er, I've – already done it in your timeline, and you've felt the effects. You can't cross timelines and alter an experience in your own past. Just running into ourselves is bad enough."

"I know, but we can still fix things in the present, _my _present. The psychic distress call—"

"That was from her?" Martha asked.

"She couldn't have done it as a human. It can only mean her memories have been triggered, and her Time Lord consciousness is coming back. And it has to be bad if she's far enough along for me to sense her even in a parallel reality."

"We think whatever's causing the walls between worlds to break down has somehow broken down Donna's memory lock," Rose picked up where the Doctor had left off. "We know the Doctor – the other one, two hearts – is around somewhere because Donna had an impression of him going into a restaurant with Wilfred, her granddad. But we don't know why he's not helping Donna. We think he's busy with whatever caused the crisis in the first place."

"Our plan is to slip in while's busy with that, rescue Donna, then figure out what's bringing the time streams into disarray and help put an end to it," the metacrisis said.

"We may have to rescue the Doctor's other half as well," Rose added.

"If Donna's this far gone, it'll mean he's in some sort of trouble," the metacrisis agreed.

"All right, so what do you plan to do once you find her?" asked the Time Lord Doctor. "You can't very well wipe her memory again with the psychic scars from the first erasure still in place. You'd have to block even more of her memories just to prevent her noticing the inevitable quadrupled _déjà vu_ effect and undoing it all again."

"No, and I wouldn't do that to her, even if I could, which I doubt." The metacrisis Doctor's time sense and telepathy were both weaker as a human, and while his connection with Donna was exceptionally strong, he suspected fiddling with her memory was beyond his capabilities. Not that it would have mattered. "It was like killing her. It meant killing who she was, which comes to the same thing. He shouldn't have done it. We didn't have the right."

"What other option is there?"

Rose answered. "The Doctor's been working on a sort of cryostasis chamber in our TARDIS. If we can get her in there, it'll buy us some time to come up with another idea."

"That doesn't sound like much of a plan," Martha said doubtfully.

"No, it doesn't, but then that's par for the course for us, isn't it?" The corners of the Time Lord Doctor's mouth twitched up almost imperceptibly. "Well then. Rose Tyler and the Doctor 2.0, running without a plan, saving the world one unlucky bride at a time. Martha and I had better tag along."

"What? Why?" Martha asked, genuinely surprised.

"I'm still a fully expressed telepath, unlike him. At the very least, I can keep her stable until we get her into cryostasis. And besides, since our dinner plans are looking less and less likely, I think it's only fair that I get one last adventure with my old companion," he said, meeting Rose's eyes with a quiet smile.

Rose felt the phrase "old companion" drop into her stomach like a stone, and she resolutely tightened her grip on the human Doctor's hand to remind herself he was there. The Time Lord was already distancing himself, just as he would on the beach at Bad Wolf Bay two years from now in his timeline, separating himself from her in order to leave her with his mortal form. Watching him put on that mask of a smile as he told her it was a good thing, slipping away into the TARDIS while she wasn't looking, and then taking off without saying goodbye – It felt wrong then, and it felt wrong now.

"Right, then!" The metacrisis took a deep breath, finally breaking the silence. "The four of us, back to the TARDIS 2.0. Allons-y!"


	10. Chapter 10

The TARDIS 2.0 looked exactly like the first TARDIS on the outside and in the console room, but once you took the spiral staircase down to the corridor, it became clear that there were far fewer rooms and a whole lot less clutter. She'd only had a little under a year to grow and become usable, and she hadn't been to too many places yet since becoming space-worthy.

They materialized on the street only 500 meters or so from where Donna lay crumpled on the pavement, ringed by equally unconscious neighbors who had, until recently, carried the face of the Master. They'd been closing in on her when she'd suddenly emitted a golden energy pulse, knocking back her attackers and sending the metacrisis a confused jumble of panicked images through their bond a universe away.

Now the fallen humans bore their regular visages, and the sky crackled with a foreboding energy.

The moment they landed, the Doctor and the metacrisis knew something was wrong. The Doctor blanched dramatically and leaned on one of the control panels at the center console.

"Doctor, what's wrong?" Martha asked in immediate concern.

"This is not good," the metacrisis mumbled instead. He, too, had gone pale, though to a lesser extent than the full Time Lord. "This is _very_ not good. Time is bending and warping all over the place."

"This can't be real," the other Doctor added in a whisper, sinking lower as he gripped the console with both hands. "I can sense them."

"No, that's impossible. They're all dead. We're the last. It can't be what it feels like," the metacrisis gave a half-hearted smile.

"You're only getting this half-strength and you recognize it, too," the Doctor argued back. He pulled himself back up and lurched toward the door. "The other one's going to need us."

"No! You're too close to him in your timeline. You'll set off a paradox. You stay here – Rose and I will go out and get Donna. Martha, watch him!" He pointed at the other Doctor and ran out the door, followed closely by Rose. Martha nodded and put an arm around her Doctor's back to steady him. She knew traumatic shock when she saw it.

Rose and the Doctor quickly picked their way around the fallen bodies in the street and made for the collapsed ginger a little ways away.

"Should I call the other Doctor?" Rose asked, adrenaline pumping. "Like the old yousaid, he's gonna need help."

The Doctor shook his head. "We have to mitigate the risk to the timeline as much as possible. We have to send my past self back out of the danger zone first. Anyway…" he let out a deep breath. "One Time Lord, multiple versions or not, can't possibly take on an entire army of Time Lords head on. And unless myself and I are seriously mistaken, that's what we seem to be dealing with. We need a strategy first."

They reached Donna and rolled her on her back to quickly check for a pulse. It was there, but erratic.

"C'mon, we've got to get her to the TARDIS." The Doctor picked her up under her shoulders and Rose had just grabbed her feet when a dark planet moved through the veil of time into Earth's orbit and blotted out the sun. It was massive, orange and blood red and burning, so huge that the sky couldn't hold it.

The Doctor and Rose looked up at it in horror.

"…No…"

"Oh my god, is that…?"

He nodded speechlessly.

Rose looked away from the monstrosity in the sky to turn to the Doctor, ready to ask if this could be a good thing, if there were any chance of help, if he had allies or friends there, if they could now do all those things that the Time Lords in their heyday had been able to do back when there was more than one of them, like travel between parallel worlds and fix paradoxes… But the look on his face answered all her questions.

She'd known there was a war, and that he'd felt it necessary to destroy his own planet and sacrifice his own people in order to end it. She'd guessed that the majority, or at least the leaders of his planet hadn't seen things the same way. But he always spoke of the planet so fondly. She'd thought he might be glad to have it back.

In all the time she'd known him, he had never looked so terrified.

"Doctor…" she began.

He broke himself out of his frozen trance. "Right. Let's get going."

Between them, they hoisted Donna up off the street and took off for the TARDIS as hastily as they could manage.

The Doctor willed himself not to look back over his shoulder at the monstrous orange planet looming impossibly over the tiny Earth below. He wanted to go back, to find out what was going on and put a stop to it. He knew the Time Lords couldn't have come back without bringing the war with them, and that their plan for the Ultimate Sanction wouldn't have changed. The only thing stopping him from running straight towards it right now was that he knew the other Doctor, his contemporary Time Lord self, was somehow already involved, and that Donna wouldn't stand a chance if he didn't help her first.

"We've got to get her into stasis. Then we'll send my younger self back in the TARDIS 2.0 to keep him out of the line of fire, so we don't have a paradox on our hands if he gets hit, and I'll hunt down my other self here."

"What about me? I'm going with you."

"You'll be safer with him. Rose, this whole place is going to be crawling with Daleks, Skaro Degradations, Never-weres, and Meanwhiles any minute now. Those on the Time Lord side will be just as deadly as their enemies to anyone on Earth."

"And am I wrong, or can't they time travel, too? How is 2007 any safer than staying here with you?" Rose said curtly. "And in case you forgot, you're human now, just like me. You're not staying to face any danger I can't face."

The Doctor paused and looked at her, and then shook his head and smiled ruefully.

"You're right. I forgot. You don't stay put when I send you back, anyway. No point trying, is there?"

Rose grinned back. "Nope!" she said, popping the 'p'. She gave him her best cheeky tongue-in-teeth smile. Despite the foreboding mammoth in the sky, the enfeebled time senses screaming in his head, his best mate dying in their arms, and the near certainty that all life in the universe would be wiped out in the next couple of hours, the Doctor felt his spirits lift a little. Stuck at the end of time itself, with Rose… not so bad.

As they neared the TARDIS, Martha ran out and helped them drag Donna inside. The other Doctor was poised over the controls, flushed and shaken.

"They're closing access to the vortex, locking all time travelers in place. If we don't leave now, we'll be trapped," he said in a rush as soon as they were through the door.

"We've got Donna, just get her into the stasis chamber," the metacrisis replied. "I'm going back out to find your future self and give him a hand."

"Me, too," added Rose.

"Too late," the Time Lord cried. The ship gave a lurch and the dematerialization sound echoed through the interior. "She just took off."

"What are you doing?!" the metacrisis cried, rushing to the viewscreen. "We're in the vortex!"

"I didn't do it! She's taking instructions telepathically. Oh, that should not be possible…"

"Donna," the metacrisis shouted, eyes wide. "It's Donna. She knows she's dying, she's trying to bolt. C'mon! We have to get her to the chamber!"

"Even _I _can't fly the ship telepathically!" the Time Lord shouted as they awkardly ran through the corridors carrying Donna between them, closely followed by Rose and Martha. "She's not even designed for that!" 

"Yeah, well, you're not burning up your brain using all your mental abilities simultaneously without restraint, either!" huffed the other Doctor. They pulled up next to the cobbled-together mismatch of 20th century and 53rd century parts that made up the cryostasis chamber, which resembled a human-sized plexiglass tube with the top cut out. Not wasting any time, they dumped Donna in without ceremony. The metacrisis immediately whirled around to the controls and ran a quick scan.

"Her telepathic field is registering at basic 85… 89… 92! No wonder her brain's melting. She's running at ten times what we can handle and she hasn't got the physiology to turn it off!"

"Increasing the hydrostatic pressure. Neurofeedback interface attached. I'm reactivating her intracellular enzymes." The Doctor leaned across the module and adjusted several dials. A loud hiss and a wave of white fog whooshed out of both ends of the tubes, partially obscuring Donna from view and leaking out over the sides of the opening to drift lazily down to the floor grating.

The Time Lord Doctor bent over the local display and monitored her vitals and brainwaves.

"Is she okay?" asked Rose.

"The system is slowing her physical functions, but her brain's still running amok. It's too late –her Time Lord consciousness has fully re-emerged. Even in cryostasis, she's subliminally aware of her surroundings, and she's processing at a higher rate than a human can handle. She won't last more than a few minutes."

"Donna, hold on!" the metacrisis grabbed Donna's shoulders and pleaded with her. He turned to his earlier counterpart with desperation. "Telepathy. You've got to help hold it back."

The earlier Doctor immediately reached in and fanned his long fingers over Donna's temples and jawline, focusing his eyes on her face as he spoke to the other. "I'm only slowing the inevitable, so you'd better think fast."

The fog in the chamber settled and suddenly Donna's eyes flew open and she gasped, then let out a long scream that seemed to go on and on.

"Doctor!?" Martha rushed over, hands over her ears as Donna continued to scream.

"Donna!" cried the metacrisis. "No, no, no, I've got to think…"

Rose, wincing at the high-pitched wail, took one of Donna's hands and held onto it. The Time Lord Doctor closed his eyes and tried to concentrate, suppressing Donna's memories as much as he could. Erasing them or locking them up again was not even in the realm of possibility. She'd come back too far.

"Hurry up!" he called to his future duplicate.

"Ohhhh! Think, think, think! Excitatory neurorecepter overload, pentameric ligand-gated ion channels collapsing, but she can't process the temporal feedback from the probability subspace field! I don't know what to do!"

In the background, Donna's scream cut out and she began repeating herself, staring wide-eyed through the ceiling straight ahead of her face. "No, no, no, I can't go back, don't make me go back, please don't make me, please don't make me, don't make me, make me, make me, make me, make make make make make…"

"Can't you wipe her memory again, just to buy time?" Rose asked the Time Lord, urgency in her voice.

"I can't, her brain's too active. It's already past stopping now. She's throwing as much telepathic force back at me as I can handle, and then some."

"Would retcon work? If we stopped by Cardiff again, got some from Torchwood 3—"

"We might wipe her memory, but the consciousness will remain. She'll still be able to see all of the past, the present, and every possible future timeline. That's the problem. Her human brain can't handle the Time Lord consciousness, and I can't lock it away again."

Martha looked between them helplessly, her arms cradling Donna's head as the woman convulsed again. In the background, Donna continued to chant 'make make make make make' at a rapid pace.

"Well, if being human's the problem, can't you just, I dunno, make her into a Time Lord? Use that Chameleon Arch in reverse, and change her species to one that can handle it?"

The metacrisis, still pacing by Donna's feet and muttering to himself, rubbed his hands back and forth violently through his hair as he answered Martha. "No, no, we can't use the Arch, it's doesn't work that way. It's only programmed to transform Gallifreyans into humans, and not… Martha, that's it! You're brilliant!" He leapt up into the air suddenly, grabbed Martha's shoulders, realized she was still busy cushioning Donna's head, took Rose's hands instead and spun her around in a sort of happy circle dance.

"The Chameleon Arch is designed to work one way, and one way only – Time Lord to human – wouldn't do to have alien species turning themselves into Time Lords and running all over time and space, regenerating into Rassilon knows what, changing history to suit their whims, would it? 'Course not, Gallifrey wouldn't stand for it, inferior species that you all are. So they designed it with a limiter. But we don't need to turn Donna into a Time Lord – we only need to remove the Time Lord consciousness. Martha, what happened to my consciousness when I became human to hide from the Family of Blood?"

Martha's eyes widened in understanding. "You went into the fobwatch!"

"Exactamundo! We put Donna in the Arch, pull her Time Lord consciousness into a receptacle, and presto! One human Donna, human memories intact—"

"But without the Time Lord consciousness!" Rose shouted happily, excitement bubbling back up.

"Without the Time Lord consciousness!" he confirmed, beaming at her, but less elatedly than she would have expected. "There's just one teensy little problem."

Rose's enthusiastic grin faltered slightly. What was it? She looked at the other Doctor, and saw only a solemn, steady gaze at his identical twin. Suddenly she looked back at her own Doctor, frightened.

"What is it? What's wrong?"

"The Chameleon Arch is only designed to change Time Lords into humans, not humans into humans. To trigger the transformation, we're going to need to use Time Lord DNA as the starting material in the machine."

"So? Donna's got Time Lord in her."

"She's only got the consciousness, not the genetics. It's not enough."

"The target will have to be at least halfway Time Lord, or the transformation sequence won't trigger," the other Doctor broke in. "Functioning properly, only a full Time Lord would be able to set it off, but with a bit of tweaking, I think we can convince the machine that the process was already started and interrupted halfway through, and it only needs to finish the job."

"I'll have to be the one to trigger the device," the half-human Doctor explained.

"And? What'll happen to you?" Rose asked fearfully. Her hands shook. She had a feeling she already knew the answer, but didn't want to believe it.

"I'll… return to where I started," he said with forced lightness. He looked off to the right, avoiding her eyes.

"What's that mean? 'Where I started?' Doctor, look at me. What's that supposed to mean?" Rose's voice started to rise in pitch.

He dropped his gaze to the floor and scratched the back of his neck uncomfortably, and didn't answer. That was all the confirmation she needed. Something in Rose snapped.

"Doctor! You promised!"

"Rose…" the other Doctor tried to step in, but Rose shoved him away and grabbed her own human Doctor by the lapels.

"You promised! You said you'd spend your life with me!" Her clenched fists shook angrily. "That was our deal! That was my forever! You can't! You can't!"

Together, the Doctors pried her fingers from his suit jacket and the Time Lord Doctor held her from behind, arms wrapped around her kindly but securely as she struggled and fought.

"You can't! You promised! You promised!"

"Rose," said the metacrisis Doctor sadly, "It's the only way. You still have a version of me. The original version! Even better! The Doctor's right there." He waved his hand with an effort at enthusiasm, indicating the Time Lord holding her in his arms. "You'll still get forever. I – he won't desert you. He wants you with him. He would've taken you with him back on the beach if I hadn't been in the way. It broke his heart to leave."

"Nooo!" she wailed. "He's not you!"

"He's more me than I am," The human Doctor gave her a lopsided smile. "Rose. I have to do this. Donna gave me life. I can't sit by and watch her die. Her and me – This isn't how we were meant to be. Donna's meant to be whole, and I… Well, the universe doesn't need two Doctors."

"What about what I need?" She'd stopped struggling now and just looked broken. Mascara ran down her face in little smoky rivulets. She stared at him in despair. "You said you loved me."

The human Doctor reached forward and raised both hands to her temples, bowing his head and touching their foreheads together.

"Rose, I love you more than I've ever loved anyone else in the entire universe. You know I wanted to spend my life with you. This is my forever. It just… wasn't as long as we thought."

She closed her eyes, leaning into his touch, and another tear rolled down her cheek.

The metacrisis turned and steeled himself, ready to begin. "Let's move Donna into the console room and get started."


	11. Chapter 11

Rose watched, still crying softly but refusing to look away as the metacrisis lowered the Chameleon Arch from the ceiling and snapped a silver fobwatch into a slot on the side with a click. He knelt down on one knee and took Donna from his original self, holding her under the knees and shoulders against his chest. She'd drifted back into unconsciousness, but she was burning up, radiating a bright golden glow.

The two Doctors' eyes met, and the Time Lord gave his half-human duplicate a respectful nod.

"I'll take care of her."

"I know."

His eyes traveled over to Martha, who was standing against a coral strut, bracing herself sadly. She remembered how the transformation process went last time, and she wasn't looking forward to watching it again.

"And…" the metacrisis continued under his breath to his counterpart, "I know you won't remember this, but be nice to Martha. You won't find a more loyal friend than her, and the next year is going to be hard."

The Doctor frowned worriedly at the portent behind his words, but nodded again.

"Are you ready for me to turn it on?" he asked.

"Yeah, do it."

Martha turned away and rubbed her eyes. The Doctor moved towards the control panel.

"Doctor!" the metacrisis called suddenly. It was strange to hear his own voice calling his name. "If… if there's anything left of me… if any part of me does make it through, it'll be in the watch. I… I want Rose to have it."

Rose strangled a sob, and forced a valiant smile. "I'll keep it safe. Forever."

The metacrisis, eyes fixed on Rose, smiled and nodded.

The Doctor threw the switch. Donna and the Doctor immediately began to scream. A rapidly flashing white light grew out from the center between them, and quickly grew bright enough that despite her inner resolution to watch, Rose had to cover her eyes. Donna's and the human Doctor's screams rose together as the agony increased. Martha curled further into the curving wall, wishing she could block it out. The Time Lord at the control panel only watched in stony silence, respectfully bearing witness to his duplicate's sacrifice to save a friend.

After what seemed like an eternity, the Doctor's screams faded and only Donna's remained, shrill but rasping now as her voice gave out. Finally, even that faded and all the lights in the TARDIS flickered and went out.

A few seconds later, the TARDIS usual blue-green glow returned and everyone's eyes readjusted to the light. Rose was the first to dart towards them, throwing herself forward on all fours on the hard grate of the TARDIS floor during the transformation. She reached the center where the machine had been, and pulled back, hands flying to her mouth and fresh tears welling up in her eyes.

Donna lay groaning on the floor, her red hair fanned out over her face. Beside her, there sat a severed human hand, and nothing more.

The machine dinged and a light over the little slot holding the fobwatch turned green. Rose leapt for the empty, hanging device, gingerly detached the fobwatch from the side, took it out and cradled it softly against her chest, heartbroken.

The Doctor, meanwhile, kneeled down next to Donna, who was just coming to. Martha came over to join them and check on Donna's vitals.

"Ughhhh… Doctor?"

The Doctor smiled. "Welcome back."

"You… right… bastard!" she struggled into a sitting position to shout, and then winced and held her head. "Ohhhh, if my head wasn't hurting so badly right now, I would knock you into next week!"

The Doctor raised his eyebrows and hummed admiringly. "That's the old fighting spirit, Donna! Mind you, I haven't actually done anything to deserve that sort of violence yet. Seems a bit premature to threaten me at this point."

Donna narrowed her eyes at him in annoyed perplexity, and looked around. She saw Rose hunched stiffly over something a little ways away and frowned confusedly.

"Is that Rose? What's wrong with her?"

The Doctor fell silent. Since he didn't seem inclined to illuminate the situation, Martha drew in a breath and did it for him. "We… just lost someone."

Donna turned at her voice, suddenly noticing the petite woman on her other side, and then looked at them both in quiet sympathy. "Seems I'm always meeting you just after you lose someone. Who was it?"

The Doctor tugged his ear uncomfortably. "Er, me, actually."

Donna gave him another bewildered look and turned back to Martha. "How does that make any sense? Martha, can you translate for… Ohhhhh." Her eyes widened as comprehension dawned and she fell silent. She remembered leaving Rose with the metacrisis on the beach before flying away with the other Doctor. Now here was Rose, back in this world, with only one Doctor nearby.

"Which one are you, then?" she asked quietly. "Human, or…"

"Time Lord," he answered.

"Then the other one, with my DNA in him…" Donna trailed off, watching Rose from the back. A sense of gloom resettled over the control room, and no one said anything for a few minutes.

Martha broke the silence first in an effort to lighten the atmosphere, or at least move the conversation away from the inevitable question of how he'd died. "So! Another one I haven't met who knows who I am. How famous am I in the future?"

"What are you on about?" Donna asked, brows furrowed.

"Martha hasn't met you yet," the Doctor explained simply, glad of the distraction. "And I've only met you the once, myself."

"You what?" she goggled at him.

"Time travel," said Martha, nodding in a what-can-ya-do kind of way.

"Well, obviously time travel." She looked him up and down. "'S not like you ever change, so there's no telling which 'you' this is. Human, alien, past, future… So if you haven't traveled with me yet, when are you from, then? My past?"

"Yep!" chirped the Doctor.

"After Lance?"

"Definitely after."

"Before Adipose Industries?"

"Never heard of them."

"Then how did you know to come get me? And hold on a minute," she gestured to the Doctor with renewed ire. "Does this mean you-in-the-future knew the whole time that you were gonna come back in your past to return my memories? And you let me think I was gonna die, or get wiped out of existence forever, without even a _hint _not to worry? 'I'm so sorry, Donna, you can never come back? You can never remember?' I suppose that was funny to you, was it?" she hauled herself up using the TARDIS console for support and pointed at him threateningly.

The Doctor rubbed his hands over his face and tiredly picked himself up off the floor. "Ah, lovely, we're all back to normal." He pretended to have something terribly important to handle on the far side of the room and busied himself toying with some buttons on the opposite wall in an attempt to escape the rest of her rant.

"Oi! You can't walk away from me, mister! I know where you live! And I'm not getting off this boat again without a… a remote control or something so I can bring it back whether you're willing or not, you can count on that!"

She suddenly remembered Rose sitting frozen and isolated like a statue, facing away from them just a few meters away, and lowered her voice. Watching the blonde, her expression softened, and she asked Martha, "Is she going to be all right?"

Martha shook her head, and sighed. "I don't know," she said, concern in her eyes. "I mean, I've only known her a few hours. But it… it didn't go well."

"What happened to him?"

"He wasn't…" Martha shifted uncomfortably, trying to think what might be the most tactful way to answer without putting any undue burden on Donna. "He said he was an extra, and she could stay with _him._" She jerked a thumb over her shoulder to indicate the Time Lord on the other side of the room. "Then he just sorta… disappeared into the Chameleon Arch."

Donna's gaze on her held steady. "You mean he sacrificed himself again. For me, this time."

Martha pressed her lips together and nodded.

"That stupid, alien git. I would smack 'im one if he…" She looked down at her hands. "He didn't have to do that. There had to have been another way."

Martha shrugged dispiritedly, not knowing what to say.

"An' I suppose he waited for the last minute before telling anyone what he was planning!" she continued, drawing herself up indignantly. "Typical! He thinks he's some kind of god of the universe, can make all the decisions for everybody, all on his own, but he isn't half clueless most of the time."

While the two companions got acquainted, or possibly re-acquainted, the Doctor slowly circled back to the console and wandered over to the viewscreen to assess their situation in the vortex. Right before they'd taken off, he'd sensed thousands of other Time Lords, and then the TARDIS had alerted him that the time vortex was about to be closed off to all time travelers, something that could only be done with the Eye of Harmony. He didn't see how it could be possible, but somehow, Gallifrey must have come back. That would definitely explain the weakening of the walls between parallel worlds. Time itself would have had to have come undone for such a thing to even be possible.

Now, however, as he monitored the time vortex and experimentally entered various time-space coordinates, he could see no sign of a vortex lock or even any damage to the time-space continuum. The breaches between universes were perfectly sealed. It was as if Gallifrey had never even existed, which, if the Time War and its combatants had somehow been returned to the time locked pocket dimension he'd forever trapped them in, would technically be true.

He shook his head, telling himself to stop thinking about it. He would find out about it soon enough, as soon as his personal timeline caught up to where his future self was in 2009. He would be there, _had been_ there, and had clearly done something to stop it. While that in itself was somewhat reassuring, the whole fact that it had happened at all left him deeply unsettled. But he couldn't get involved, not without crossing his own timeline and potentially setting off a paradox that would unravel the entire universe. He'd have to leave it alone, and cross that bridge when he came to it. He had problems enough here in the meantime.

He turned back from the computer screen and looked at Rose. She stood motionless before the Chameleon Arch control, still staring fixedly at the fobwatch in her hands with her back to the other occupants in the room. Her eyes were hidden by her fallen hair, but her whole demeanor was that of a woman completely and utterly lost.

He itched to comfort her, but stayed where he was, tugging his ear awkwardly instead. They needed to talk, but not with Martha and Donna hovering around and her lover's disembodied corpse hand lying on the grate a few feet away. Best to get the TARDIS somewhere safe first, let out the other passengers, and just confirm that the timelines were really secure again.

"Looks like the vortex lock is gone," he said lightly to the room in general. "I'll just bring her down back where we left, 2007, have a quick look around, see that the timelines are intact, that sort of thing."


	12. Chapter 12

**Didn't quite like leaving things on that last chapter, so here's another! Two in one day!**

* * *

They landed in Cardiff about an hour they left.

"Well! Back to the proper TARDIS, I suppose," Martha said in relief, straightening her jacket as she stood up from the jump seat.

"Not that any of my things will be there," Donna said glumly as they filed out of the TARDIS. "No, in my time, that sod's off gallivanting around time and space with half my winter wardrobe gathering dust. Not that it'd occur to 'im to drop my stuff off with me when he left me at home. Mind like a sieve, that one."

"Did you notice when you lost your memories? Was it obvious that things had disappeared or changed, I mean? That time had passed?" Soon to experience it herself, Martha couldn't help feeling a tad apprehensive.

"Nah. Well, I did wonder where my chartreuse handbag had gone off to. Now I know I burned a hole in the bottom of it on Hastus Minor when I set it down on some kind of thermal vent thing, and had to throw it out. But I was always missing things, before. I'd come back from scuba diving and everyone would be talking about an alien invasion or something like that. It didn't seem that unusual. And whenever I started to think about it, I got this headache right behind the eyes, like wondering too much was dangerous for me. That's all his fault, of course."

A new thought occurred to her, and she turned to look at Martha. "Hold on a minute, did you know about this when we went to that planet where…" she glanced back in through the open door of the TARDIS at the Doctor, who was still dillydallying around the console, and lowered her voice to a hushed whisper, "the one where we met Jenny?"

"Who's that?" Martha whispered back, having no clue what the redhead was talking about, but gamely enjoying the mystique of the whole conversation anyway.

"Never mind that. Just tell me, are you gonna remember all this when you meet me properly? Or does he do his alien memory wipe thing on you, too?" She wiggled her fingers at eye level to indicate whatever psychic alien mumbo jumbo the Doctor had done to her. "If he comes at you with his hands up like this, you just better watch out. Don't let him overawe you. He'll try to push you around, but you just got to give 'im a piece of your mind."

"Right. I see. Okay." Martha nodded slowly with a smile, still a little bemused by this strange woman who talked to her like they knew each other well.

Donna folded her arms and added conspiratorially, "Seriously, now, you've got to stick up for yourself. I know you have a bit of a thing for him now, but trust me – you'll find someone better. Just wait til you leave 'im."

"I – Wait, What? I never…" Martha flushed in wide-eyed alarm, glancing frantically at the TARDIS to make sure the Doctor was still inside and out of earshot. "Hold on, did you just say I was gonna…?"

"Oh!" Donna gave a little gasp, suddenly self-aware. "Oh no, I shouldn't have said anything! Don't mind me! I could change things just by saying."

"Well you certainly can't start a sentence like that and then just back out!" Martha objected.

As Martha and Donna gossiped on just outside the TARDIS on Roald Dahl Plass, the Doctor turned and walked back over to Rose. She was sitting and staring desolately at the fobwatch she held tightly with both her hands in her lap.

"So, errrr… Rose," he stopped a few feet away from her and scratched the back of his head. "I've sent out a temporal ping to the future TARDIS… Not really supposed to check on that, can't risk knowing too much about my own future, but I was able to make sure the future me's still around after whatever happens in 2009. Not sure what kind of shape the TARDIS' in, or I'm in, but she says we're alive, so you can travel ahead to join up with us."

He poked a few buttons on the TARDIS console absentmindedly, nervously filling the silence with more words.

"I mean, of course I'd rather have you with me now. It's not like I'm sending you away again. It's just that I can't take you with us in the regular TARDIS without altering your past and my future and creating a paradox, but since you brought your own TARDIS – quite nice, by the way, I like what you've done with the place – I can program it to take you forward a few years, catch you up with future me right after where we just left him in my subjective linear timeline. I'll have to wipe my memory to protect the timeline, but I'll set it up so a trigger word from you will restore it. What d'you think would make a good keyword? Shiver and Shake? Applegrass? Maybe Bad Wolf, I suppose that would be appropriate…"

She hadn't moved or looked up from the silver trinket held in her lap. He meandered closer and crouched down next to her, studiously contemplating the nearest coral struts rather than attempting to meet her eyes, which he feared might hold something he didn't want to see.

"Donna will have to go with you," he continued, since she still didn't seem inclined to speak. "I'll calibrate the TARDIS to my own bio-signature and personal timeline, so you won't have to worry about materializing too far away or missing me if I've just left or anything. We can't interfere with Donna's timeline either, so I'll set it two hours post-event. That should be enough time—"

"I'm not going," Rose said quietly. The Doctor immediately turned to stare at her, silently panicking inside. The paranoid nightmare he'd been having ever since he'd changed from his ninth form to his tenth was finally unfolding before him in real time.

"What? You don't mean that," His mouth twitched in an attempt at a nervous smile. "Rose, we can be together again, like you said—"

"No, we _were_ together again, and now we're not. Now he's a… he's nothing but a hand and a watch, and I'm left behind, _again! _I'm not leavin' him to go swannin' off with some future you! An' you should know, Doctor, that what you did – what you _will _do, droppin' us off on the beach after saving the Earth and then just flying away… It doesn't work that way. You can't just swap people in and out like that. It took him and me ages to work through that!" She clenched her fists, furious, holding the fobwatch tight against her chest.

The Doctor scrambled to his feet and quickly backed away like he'd been struck. "I… I… Right, of course you're right, I don't know what I was thinking. You wouldn't want to… What with everything I've put you through, your family, losing your whole life here and all, and then your parallel world… And he was human, could give you a family and real life and…"

Rose watched him fumble miserably and felt her anger fade. This was so like him. He never understood humans, close as they were.

"Doctor, it's not that," she said, softening her tone and reaching out for his hand. "It was never about that. I would've stayed with you forever. _This _you. The Time Lord you. I didn't need you to be human. It was you who needed that. But the thing is… We were buildin' a life together."

He gazed mournfully into her eyes. She smiled sadly back. "I know you and he are the same man – if you weren't, this wouldn't be so complicated. But I won't betray him like this. I just can't."

They stood like that for a while, silently contemplating each other. Finally, the Doctor looked down at their interlaced fingers, and then up at her face again.

"Show me the fobwatch?" he asked after a moment.

Rose handed it to him. He took it, closed his eyes and listened. There it was, faint but unmistakable. His own voice, but not his own, echoing telepathically in his ears.

He handed it back to her. "I didn't want to get your hopes up, because the odds of it working for a human-Time Lord hybrid aren't good, but he's in there."

"He is…?" Rose perked up a bit, afraid to hope, but the old familiar optimism was rising in her chest.

"There might be a way to save him, if… if you want."

"Of course I want to save him!"

"It's not… That is, I can't bring him back. That isn't possible. But his consciousness is a match to mine. I could open the watch and take in his memories and consciousness. We'd be merged again, like we were originally. I'd be him, and… and me."

"And he'd be there inside you? I mean, you'd remember everything we did, everything we said and experienced together since we separated from the future you? _His _opinions, _his _feelings and thoughts and experiences, not just the knowledge of what happened, but his actual consciousness would still be alive somehow?"

"Yes. But he – he wouldn't be human anymore. He'd be a Time Lord again. Essentially un-aging."

"I don't care about that. I just want you to be you. Both of you."

The Doctor's mouth twitched up in a lopsided grin. "So, basically, rude and not ginger."

"Exactly." Rose smiled, leapt into his arms, and flung her arms around his neck. He wrapped his around her waist and shoulders in response, and planted a light kiss into the side of her neck.

When she finally pulled back, she ran her hands over his pinstriped sleeves and looked him up and down.

"Okay, then! What do we do?"

"It's better if I don't do it here – now, I mean, in this time. I still have to lock away my memories of you to prevent a paradox, and that's a tricky process at the best of times, without trying to simultaneously integrate dual sets of memories. Moreover, the future me is the one who lost a bit of himself when he channeled the regeneration energy into that hand – he'll be missing a chunk somewhere that our little friend here will fit right into. Me, on the other hand – I haven't lost him yet. Might not be a lot of extra space upstairs to put him in."

"Okay, so I have to bring him to the other you. The future you."

"Right. You say the password to trigger my memory recall, I open up the watch, and there you have it! One recombined former-human-Time-Lord-hybrid-slash-full-Time-Lord. Blimey, that's a mouthful."

"Let's not use 'Bad Wolf' for the key," Rose said with a grimace. "You're still going to meet past-me before I run into future-you, and I have a feeling you might hear the words 'Bad Wolf' a little too early."

"Did I ever tell you, I love the temporally complicated nature of our relationship?" the Doctor asked, grinning cheekily.

"Why do you think I'm with you, you daft alien?" Rose teased back, smiling. "'It travels in space,' you said, and I stay to take care of Mickey. 'It also travels in time,' you add, and I run off with you like a shot."


	13. Chapter 13

The Doctor programmed the TARDIS 2.0 to take Rose and Donna to his future two hours after the complicated space-time event which precipitated their rescue of Donna. This was easier to manage than one might expect; he simply had to enter the time-space coordinates of Donna's fall into his own original TARDIS' computers and program it to send out a homing signal to the TARDIS 2.0 two hours after leaving those coordinates. Then the TARDIS 2.0 would only need to pinpoint and track down source of that signal in space and time. Easy.

"I guess this is it," Rose said, twisting the fobwatch chain around her fingers awkwardly. She had threaded it through the necklace chain that held her TARDIS key and was wearing it like a pendant. "I know I'm gonna see you again soon as we land, but…"

The Doctor gave her a smile. "It's going to be a bit longer than that for me."

"Yeah."

They silently stood there by each other for a moment, almost touching but not quite.

"There's nothing I can say that you will remember until we meet again, is there?"

He shook his head sadly.

"Well… this'll have to do, then." She pulled him forward by the lapels and planted a searing kiss on his lips. His eyebrows shot up, but then relaxed into it and kissed her back. They leaned against each other for a long time, and then Rose finally pulled back.

"I should go," she said a little breathlessly.

The Doctor took a deep breath, secretly willing his nose to hold onto her scent as long as possible. "When you find me, just give me the fobwatch and say 'applegrass' three times. I'll know what to do."

"All right."

"Donna," he said, turning to where the other two companions had been idly chatting and deliberately giving the star-crossed couple their space. "Sorry about the whole… memory thing," he finished with a wince. "I haven't done it yet, but you know I wouldn't if it weren't the only way I could think of to save you."

"Aw, well… S'pose I can forgive you. It was to save my life, and all. _This _time." She flapped her hand at him with a crooked smile.

"Martha," he said, turning to her with a sigh.

"I know," Martha replied briskly. "Time to forget everything. It's been good to meet you," she added to the others. "I'll see you later, apparently. Maybe we can do brunch sometime after all this timeline-protection nonsense gets sorted out."

"I'd love to," Rose grinned. "Cheers!"

The redhead and the blonde walked into their blue box and closed the doors behind them. A minute later, the lights began to flash and the familiar pulsing screech of the TARDIS engines resonated around the square as the timeship became increasingly insubstantial. Martha and the Doctor stayed to watch until it had completely dematerialized.

"Well, then," the Doctor began, turning to Martha again. He raised his hands up close to her temples and paused. "If you're ready…"

Martha smiled nervously, glancing at the long fingers besides her face. "Just like she said."

"What?"

"Nevermind. I'm ready. Come on."

Ten minutes later, both of them came to in the TARDIS control room. Martha was sitting on the jump seat. She blinked slowly, coming out of a fog. What was she doing in here? Oh, right – she'd just been on her way to the control room to see if the Doctor had decided to finish his sulk yet and be sociable again. Apparently, he had, because he was standing at the console with his back to her, completely motionless.

She stood up and walked over to him. His face was totally blank, and he seemed to be looking right through the central column in front of him.

"Doctor? How long is this gonna take?"

He didn't reply for a moment, and then suddenly he shook himself like he was just coming out of a reverie.

"Hm? Sorry, spaced out for a second there. What was that?"

"I said, how long is this gonna take? Refueling the TARDIS?"

He checked the viewscreen and raised his eyebrows in surprise. The recharge was practically finished already. That was strange. "Oh, should only take 20 seconds," he said in response to Martha's question as he entered a few more commands. He wanted to scan the place to find out how the re-energization process could have gone so quickly.

He frowned as the results of the scan came up. "The rift's been active."

"Come to think of it, they had an earthquake here in Cardiff a couple of years ago," Martha said, oblivious to the mystery surrounding their easy refill. "Was that you?"

"Bit of trouble with the slitheen," he answered, temporarily distracted from his investigation by the memory of the cheeky blonde who'd been with him at the time. He immediately clamped down on the sorrow that accompanied that thought. "Long time ago. Lifetimes. I was a different man back then."

A ripple of revulsion ran through him suddenly as something unnatural disturbed the eddies of space-time surrounding the ship. He glanced down at a viewscreen showing the area outside the TARDIS and felt a surge of nausea at what he found there. Captain Jack Harkness, living insult to the flow of time itself, was running towards the ship. Forget Cardiff – no mystery was worth facing _that._

He flipped a few levers. "_Finito! _All powered up," he said with false cheer, and with that, he threw the ship into the vortex as quickly as he could.


	14. Chapter 14

**Since there wasn't really any action in the last chapter, I'm doing the two-in-one-day thing again.**

**And by the way - HUGE thanks to everyone who's been reviewing! :D You put a smile on my face!**

* * *

Rose and Donna hurtled through the time vortex and finally rematerialized with a wheeze and a thump. Rose picked herself up off the floor and ran to the door, throwing it open to find herself on familiar ground.

There was snow everywhere, it was the middle of the night, and this was the Powell Estate.

Donna appeared in the doorway behind her. "Where are we?"

"Home. I mean, my mum's old place."

She stepped forward curiously, looking around for some clue as to what time they might be in. They were supposed to have followed the Doctor into his future _after _that business with Gallifrey coming back, but the Doctor had been known to get his dates crossed before and she reckoned that programming the TARDIS wasn't all that different from flying it.

"If this is his future, what's he doin' here? I don't live here anymore," she wondered aloud.

"Maybe he likes to spy on you in the past. A bit creepy, that. Stalker-like." Donna pulled up next to a post and pointed at a flyer stapled there. "This looks fresh. What d'you think?"

The flyer advertised a New Year's party at a local pub, and the year 2005 was splayed across the top.

"Oh, that's not good. That's before I even met him. What could he be thinking?" Rose mused.

Suddenly, a golden flashing light caught their attention, and both heads snapped round at the same time. That familiar wheeze and whir wasn't a car gearing up in the background.

"C'mon!" Rose shouted as the two ladies took off running for the source of the light. They found the TARDIS parked just around a corner, and Rose fumbled with her key to get in before it could start to actually dematerialize. Donna beat her to it with her own and pushed open the door. They both ran inside just as the timeship began taking off.

The Doctor, burning brilliant with golden regeneration energy, was hunched over by the controls, gripping his sides in agony.

As they came in, his eyes nearly popped out of his head. "What? What what _what?_" Then another spasm took him and he stumbled to the floor with a cry of pain.

Rose flew to his side. "Doctor! No, you can't be—It looks like—"

"Regenerating," he bit out, gasping between paroxysms of searing agony. "Can't—How—You—" He twisted again as another wave took him.

"But you _can't!__" _Rose fell on her knees next to where he had collapsed and grabbed his jacket, hauling him to her."Applegrass, applegrass, applegrass!"

The Doctor eyes grew wider still, if that were possible, and fixed on Rose's face. "Oh Rassilon… Rose… I'm sorry…"

"You remember, right? You remember, you promised!"

"I'm so sorry…"

"You can't change now, you won't be a match to the fobwatch anymore! Doctor, he'll die!"

"I can't stop it. I'm—" he broke off into a cry as another spasm hit him. The glow seemed to intensify.

Donna shifted uncomfortably in the background. "Uh, Rose, maybe you'd better give 'im some space."

Rose ignored her and she pulled the Time Lord more tightly against her, rocking him and pleading desperately. "Please, Doctor, please fight it, you did before. I don't want you to—to disappear forever again, like last time, the first you—I like you the way you are now. You said this form was for _me_! The pretty boy form, remember?" She laughed through her tears.

The Doctor, wracked with pain, contorted again with a gasp. The light intensified. Begging through teary eyes, Rose pulled away to drop light kisses all over his forehead, his temples, the corner of his mouth. "You _can't _change, _please _Doctor! You said you'd save him! You have to be an exact match!"

The glow was blindingly bright now, and Donna had to shelter her eyes against it. It began to spread over Rose as well, crossing between her and the Doctor where the fobwatch hung at her neck.

"Got to… move back!" the Doctor bit out.

"No! I'm not watchin' you die again!"

"Rose," Donna warned, "He's gonna blow!"

The strongest spasm yet hit the Doctor, and seemed to hold. Back arched painfully, eyes staring straight ahead, he whimpered faintly, "I don't want to go!"

Rose shook her head, tears streaming down her cheeks, and kissed him. While in mid-kiss, the light finally exploded out of him everywhere, and simultaneously, the TARDIS console sparked and blew into a multitude of little fires. A cable suspended across the ceiling fractured and fell down to hang against the floor. Donna was knocked back by the force of the explosion against the railing by the doors.

Rose, meanwhile, was still in the heart of it, mouth still firmly pressed against the Doctor's, arms locked securely around his neck and back. The fobwatch and its chain burned like molten steel against her chest, and a cold white fire blinded her and enveloped her in silence. From inside the silence, she heard singing. Then she passed out.

The light faded and Donna stumbled back to her feet. The console was still spitting out sparks, and the whole control room looked a mess. The floor tilted and heaved uncontrollably as the TARDIS ricocheted off something outside – they were clearly flying blind, here. Holding on to the railing and then the console to keep herself upright, Donna made her way hand over hand towards where she'd seen the unhappy couple lying last.

She found them both unconscious on the grate, the Doctor laid out on his back and Rose sprawled sideways across his body. Other than the fact that they were both covered in dust and debris and both looked more than a little singed, they looked okay. The Doctor's face remained unchanged.

Donna shook her head incredulously at the lovers and let out a breath she'd been holding. "You nutters will be the death of me."

She lurched over to the bodies and began clearing pieces of fallen pipe away. "You just better wake up before we crash into something, Time Boy," she said through gritted teeth, pulling her collapsed friends towards the infirmary one at a time. "If I end up fighting off dinosaurs in the Cretaceous age the rest of my life because I can't remember how to fly this thing, I will bloody end you."


	15. Chapter 15

The Doctor came to lying on the floor in the infirmary. Donna sat on a bench just over him, peering down at his face with a less-than-impressed look.

"Nice to see you back in the land of the living," she said. "Now can you pilot this bloody ship before we crash into a supernova?"

"Rose…"

"She's over there, on the low bench. I could manage her all right, but I couldn't lift you. How a skinny ponce like you can be so heavy is beyond me."

"Is she…"

"She's fine, far as I can tell. Breathing, anyway. Regular pulse. Hasn't come out of it yet, but you _would _be first, wouldn't you?"

The Doctor staggered to his feet unsteadily and made his way over to the blonde passed out on the infirmary bench.

"I'm fine too, by the way, since you didn't ask_,_" Donna continued, annoyed. "Memories back, relatively unscathed from the massive explosion in the control room. You're gonna have a right job cleaning up in there. And, as I may have mentioned, we seem to be spinning out of control." The floor gave another heavy lurch as if to emphasize her point.

"She absorbed a lot of my regeneration energy," the Doctor said, setting up equipment for a medical scan.

"Is that why you didn't change, then?"

He nodded silently, intent on his work.

Catching his solemnity, Donna came over to join him in concern over the scans. "What is it? She's all right, isn't she?"

"She should be dead," he said simply. He looked exhausted, almost like he'd given up. Despite the circumstances, Donna hadn't really been worried before, but now she felt her stomach tighten a bit in anxiety.

"But she's not," she pointed out. "So something had to 'ave saved her."

He shook his head. "I don't think so." He took a long shuddering intake of breath, rubbing his face with his hands, and he suddenly looked so old and so sad that Donna felt her heart constrict even more. He turned the medical viewscreen towards her so she could see it.

"Her brainwaves are shutting down, one by one. The energy's still in her. Something's fighting it, but she's losing the battle, and I don't know how to take it out. It's only a matter of time. Donna…" His eyes suddenly welled up and Donna stopped breathing. "I've just killed Rose."

He broke down and Donna quickly swept him into what she hoped was a comforting hug, her mind racing. This was really bad, no fooling. The Doctor had never cried, that she'd seen. Granted, he hadn't been looking all that hot when she saw him last around Wilfred, but this was something else. There had to be something she could do.

"Shh, shh, it's gonna be all right," she assured him, not knowing anything of the sort. "Let's just think this out, yeah?"

He just shook in silent sobs on her shoulder.

"Look," she said, "She's still alive right now, so what can we do to keep her that way? Cryostasis? That's what you were trying with me, yeah?"

"That wasn't me, that was the other one. Your genetic offspring."

Donna wrinkled her nose. "Let's not call him that, ta. Would that work? We have the junk with us, or at least we did where we left off. That snowy place. It's still in _her_ TARDIS."

The Doctor straightened up out of the hug and took a step back, mind whirring as he looked right through Donna into the space beyond.

"Yes, that… might work. If we hurry." He bolted from the room and vaulted over the fallen cable in the control room, Donna at his heels. Hitting several levers and buttons at once, he threw them back towards their last coordinates, and the ship gave a heavy lurch and heave as it changed course. Donna stumbled to avoid tumbling over, but the Doctor was already moving and halfway back down the corridor to the infirmary. They landed just as he emerged carrying Rose unconscious in his arms.

"Let's go!"

They hurried out the doors, and Donna noted without much surprise that they had parked exactly where they'd left. They only had to follow the footprints back to the newer TARDIS.

Once inside, the Doctor carefully lowered Rose into the stasis chamber and twirled some dials. The usual white fog flowed out of the ends of the chamber and rolled down to cover her in swirling whips.

"Will that hold her?" Donna whispered nervously.

The Doctor nodded. "Unlike you, she's not tied into the timestream beyond the present. This'll slow her degeneration enough to give me time to think."

Donna patted his arm. "Good. Come on, then. Let's get you to the kitchen and have a cup of tea. You can work it out there."

Some minutes later, as Donna poured hot water from the kettle into a pair of cups, she asked, "So how much time do we have to come up with something?"

"Oh, a couple of months, I think, before her mind loses out to the regeneration energy completely. But I don't know that it's going to do us any good." He leaned forward and covered his face in his hands again. "It's really my fault this time, Donna. I mean, it's always been my fault, whenever she was put into danger because I was the one who brought her into it, but this time it wasn't just the risk. It was me. My regeneration energy. My stupid, vain attempt to keep from…" He sucked in his breath and didn't finish his sentence.

Donna brought the tea over, set it down and sympathetically rubbed one of his shoulders. "There, now, she knew what she was doing. She's seen you do it before, hasn't she?"

"It's not usually like that. It doesn't explode out of me like that unless I fight it, and oh, I've been fighting it. I've been holding it off for hours. It's supposed to be a peaceful process. You just fade from being one person into being the next, and no energy even leaves the body. But I just couldn't— I didn't want to die. I didn't want to leave." His eyes misted over again.

"Sure, and that's natural, innit?" She sat down and took up her own cup of tea. It was too bad she couldn't have retained some of that knowledge and perceptive ability that had come with being the Doctor-Donna. She rather suspected she could have solved this whole problem with a snap of her fingers if she had. She remembered knowing what she could do, and while this lovable arse might have the knowledge of the universe at his fingertips, he didn't have half the imagination to really use it. And here he was beating himself up like a hopeless twit instead of putting that brain to good use.

"Hold on," she said slowly after they'd sat in silence for a couple of minutes. "Why don't you take in the consciousness off that fobwatch now?"

The Doctor gave her a dubious look. "And what good would that do? Bring him back just to watch her die, and add his memories to mine just to know more intensely what I'm losing?"

"Oi, don't knock it. It's a good idea. You're useless right now, I can see that, but maybe he's not. Aren't two heads better than one?"

"We wouldn't be two minds anymore, that's sort of the point," he scoffed, but then reflected on it. "Although, it is what she wanted. If I can do one thing for her..." He sat at the table for a moment more, and then pushed his chair back, got up and walked out of the room. Interested to see how this went, Donna drained the rest of her cup and followed along.

The Doctor stood over Rose's prone form in the stasis chamber, brooding. He reached in and tentatively lifted the watch off her chest.

"This thing is part of the reason she's in here," he said aloud, either to himself or to Donna; it wasn't clear. "With my matching mental signature inside, it resonated with my regeneration energy and channeled some of it through to her. I'd have likely completed my regeneration if this thing hadn't siphoned most of it off."

He turned the silver fob back and forth in the light thoughtfully, and then lifted it over Rose's head and took it back over to where Donna hovered on the infirmary threshold.

"He's talking to me."

"Are you gonna do it, then?"

"Yeah. Here goes."

He flipped open the fobwatch.


	16. Chapter 16

He stood on the beach. It was cold and starting to drizzle. Rose stood with her back to him a little ways ahead, staring desolately at a square TARDIS-sized mark left behind on the sand. He walked up on her left and took her hand, to remind her that he was still here, and to remind himself that he had not, in fact, just lost the only thing he had left in the universe with the departure of that precious blue box.

She turned to him and smiled awkwardly. "I guess it's back to London, then, Doctor." He smiled back, but spent the next 8 hours of zeppelin travel wondering whether her hesitation before the word Doctor was just his imagination.

…

Pete suggested he choose a human alias to go by. Jackie said that was nonsense, that he would never pass for human once anyone talked to him, and that he should stick with the name Doctor. The Doctor secretly decided Jackie was his new favorite person. Rose kept quiet, and the Doctor spent the next 2 hours wondering which of her parents she agreed with.

…

He grinned at Rose, made bad puns, and hopped around the kitchen table excitedly describing all his plans and ideas for the future. These mostly involved the acquisition of various alien tech they could probably find via Torchwood, followed by adjustments he could make using 21st century equipment and his own considerable knowledge of physics, mechanics, and programming. He would get the TARDIS coral growing and working in no time. They would go everywhere. She smiled at him encouragingly and he spent the next 4 hours wondering if she believed him.

…

He lay awake on the bed in the guest room at Pete's hours after everyone else had gone to sleep, just staring at the ceiling and listening for a second heartbeat that wasn't there. He kept his face carefully blank and his eyes hard because if he did break down, he didn't think he'd be able to pull himself back together again.

…

Rose caught him making that same blank face on the tube as they traveled into town to pick up some things for Tony's upcoming birthday party. He had just tried to look at another passenger's timeline out of idle curiosity and realized he no longer had that ability.

"What is it? What's wrong?" she asked, immediately intent and concerned.

"Oh, er, it's nothing."

"Are you alright?" 

"'Course. I'm always alright." He tried to cover his mistake with a wide, giddy smile.

She let it drop, but it was obvious that she didn't believe him.

…

He overheard her talking in the kitchen to her mum when she thought he was in the shower.

"I can't do that to him. It's not his fault that he's stuck here. Where else can he go? I just wish…"

That one caused him three straight days of wondering what it was, exactly, that she couldn't bring herself to do to him.

…

He stood outside the smoking wreckage of a crashed spaceship that had almost succeeded in enslaving the population of Earth. He was covered in soot and had unexpectedly painful burns all over his arm and one side of his face. He'd almost lost a hand – not _the _ hand, which would have been a great joke for fate to play, but a hand, nonetheless. Rose was so furious that she was shaking.

"You should bloody well be dead right now, do you understand that?! You haven't got any regenerations anymore! This is the real deal!"

"Torchwood's plan would've cost lives."

"And yours was less risky?!"

"This way, I was the only one at risk!"

"And that's nothing, is it? Do you have a death wish, or what?"

He glared at her, feeling wronged. "I'm not… Oh, nevermind. It doesn't matter."

"What doesn't matter? Your life? 'Cos that bloody well matters!" she continued angrily, refusing to let it drop.

He finally rounded on her. "No, it really doesn't! I'm not even—!" He cut himself off before that self-pitying statement could come out and make him look even more pathetic than he already did.

Rose stared at him openmouthed, stunned as if she'd heard the rest of that sentence anyway.

"You're not what? A Time Lord? Is that what this's about?" she said softly, horrified. "You've been so distant since the beach. I thought you didn't want to be here. I thought you regretted leaving the TARDIS. But it's more than that, isn't it? You don't want to be human."

He smiled grimly. "It's… not easy, changing species. There are things I can't do anymore that I used to do without even thinking. But I was already a burden on your family. There's no point in me whinging about something I can't change."

"And that's… that's why you're pulling away like this? That's why you keep making that face when you think I'm not looking? That's why you keep letting yourself get almost killed? Being human is that horrible for you?" She looked heartbroken. The Doctor's painfully single heart clenched at the look of sorrow on her face.

"No, Rose, that's not… I gave up the TARDIS voluntarily, and I can live with having a human lifespan, if that means living it with you."

"Then what is it? Why won't you _talk_ to me? _Properly_? I mean you've always been reticent, but these last several weeks you've been more distant than ever, and _I don't understand why_!"

"Because I want to be… I'm not… _him._"

She knew without asking who he meant.

"Yes, you are," she stated flatly, broaching no argument.

"No, I'm not. You don't even believe it. You can't even say my name without hesitating."

She quailed slightly, realizing the truth of that statement. "I… but that's…"

"There's one reason for me to be in this world, Rose, and that's you. But I'm not… I'm not the right one, I'm not the one you went back for, so…"

"Doctor," she said deliberately. "You absolutely are the right one. But this isn't healthy. You can't base your whole identity on… on what you mean to me. It's like you're having some kind of identity crisis. Oh good lord," she said to herself, hands flying up to her forehead. "Where do you find a therapist for clone envy?"

"That's just it, isn't it," he said dully, no longer bothering to hide behind a façade of manic energy. "I'm a clone."

"No, you're not a clone. You're the Doctor. Look at your hand."

He looked at the hand with the burns, since it was paining him and was rather more on his mind than the other at the moment.

"No, your other one. Is that a human hand?"

"No. The genetic make-up of this hand is 100% Time Lord."

"And which is older, your right hand, or the other Doctor's right hand? Which is the original hand?"

"That's… all right, that's a fair point, but it's only a hand. The rest of me…"

"Except your brain."

"And my brain, yeah."

"And telepathy, and your time sense."

"Those are weaker now, I can't even—"

"Can a human do what you can do?"

"No."

"Then you're still a Time Lord there, too. And am I wrong, or have you still been tasting things you find on the street to determine their chemical composition?"

"I may have done a spot analysis on a few—"

"So we can add Time-Lord-tongue, then, to the list. Anything else?"

He stared at her in disbelief for a minute, and then relaxed into an amused smile. The first _real_ smile she'd seen from him in a long time, she noted in relief.

"Okay. Point taken. I may… possibly… consider your theory that I could be suffering some sort of identity crisis. The thing is, I don't know who to be if I'm not the Doctor."

"Well, that's easy. You are the Doctor, so be the Doctor."

"I've got no TARDIS, and half my abilities are gone."

"So do what you usually do when you're cut off from the TARDIS and your abilities can't help for whatever reason. Improvise!"

…

Things slowly began to get better. He started to collect parts to make a sonic screwdriver, and laid out some designs for the first dimensional stabiliser he'd ever make from scratch. He didn't have the equipment or parts he would need, but he knew where and when to find them. He had half a broken vortex manipulator he'd dug out of the vaults at Torchwood, and a talent for bartering rides from passing spacecraft.

He showed what he'd begun to Rose with more confidence than he felt.

"I thought about what you said, about just being the Doctor… Our TARDIS isn't going anywhere for quite a while, but that doesn't mean we have to stay here too."

"Will we be able to come back the same day we leave on?"

"Well, normally these things aren't quite that precise, but no one does time travel like a Time Lord… It'll never be as comfortable or advanced as a TARDIS, mind you, but a genius like me? I'll get it targeting moments in time with pinpoint accuracy!"

"Your usual accuracy?"

"Of course my usual accuracy."

"I'll let Torchwood know I'll need a year's sabbatical."

"Oi!"

…

It was a rough trip, but they made it to the Medusa Cascade in the 403rd century in about a month of traveling, subjectively speaking. Rose likened it to camping, or perhaps traveling between youth hostels. It was an apt comparison in both cases. They carried only the essentials with them in a couple of mid-sized rucksacks, and stored their food, water, and other valuables in the Doctor's blue suit pockets, which at this point were the only dimensionally transcendental compartments they had. Travel involved a lot of bartering, more than one strategic time jump, and a few instances of stowing away. Acquiring the parts they needed was even more difficult, but manageable with some creative thinking and the timely rescue of a courtier's son.

They missed their return date by about a week in the wrong direction – they came back too early and had to hide out in a motel in Ipswich for seven days to avoid running into themselves. They passed the time watching B-list sci-fi movies and making prank phone calls to Jake and other Torchwood agents when they knew their other selves were around. The Doctor was starting to feel like himself again.

…

The TARDIS was finally starting to grow, and parts from the 403rd century sped the process along nicely. The Doctor successfully built a very basic sonic screwdriver that would do for the time being, and after several weeks of experimenting, macgyvered a way to build dimensionally transcendental pocket-space without the need for the equipment on the TARDIS. He immediately went about the process of redesigning all of their pockets and bags for practice.

…

A run-in in with a certain Sally Sparrow and Billy Shipton precipitated their next excursion into time travel via vortex manipulator, and having already gone through a similar experience in their original universe, the Doctor was able to sort everything much more quickly.

It was on the return trip from 1969 that things went all wrong. They'd upgraded the vortex manipulator to handle more than two travelers, and were just bringing Billy back to a promising life in 2008 when the transtemporal radiation deflector burned out, knocking them out of the vortex and stranding them somewhere in the 1980s.

Rose, who'd been the one manipulating the controls, took the full force of the temporal energy feedback and was knocked out instantly. The Doctor panicked. This was all his fault. He'd known using a vortex manipulator was dangerous. The whole concept behind the tech was inelegant and clumsy by nature – it was a human invention, after all, and humans had never understood time. What's more, he had been the one to upgrade the system. He'd pushed it farther than it could take. He should have known this would happen.

But Rose got up, winced over her scraped knee and singed wrist, and other than having had quite a painful shock, was apparently fine. They replaced the radiation deflector with a spare, returned to their own time, and went straight to the infirmary of the still half-grown TARDIS. A quick scan with the newly assembled sonic screwdriver showed that Rose really was just fine. The huon particles remaining in her bloodstream from her stint as the Bad Wolf had absorbed and redirected the artron energy from the blast.

…And that was the answer he'd been looking for all along.


	17. Chapter 17

The Doctor snapped out of his flashback, grinning ear to ear with brilliant comprehension. The residual huon energy in Rose's bloodstream from her bond with the heart of the TARDIS had protected her from the effects of the temporal energy feedback when the vortex manipulator burned out.

"That's it, Donna!" he whooped and grabbed her, swinging her around.

"What's it? What?" she asked, stumbling.

"Artron energy! Anyone who travels in time absorbs some. It's harmless in small amounts, just background radiation, really, but it's deadly in large enough doses. Almost killed Rose back on Satellite 5 when she looked into the heart of the TARDIS, but I managed to pull it out of her and send most of it back. That triggered my regeneration from my ninth form into this one, of course - artron energy's what we Time Lords use to regenerate and there was much too much of it in my system at that point to avoid setting off some internal biological imperatives."

"So…?"

"Huon particles, though, those are different. You know all about those!"

"I… what? Why would I know anything about that!" she extricated herself from his dance and walloped him one across the chest. "And stop draggin' me about, and speak sense!"

"Huon particles, Donna! You were full of them when I met you! The Racnoss had been dosing you, shook you up, and you teleported on board my TARDIS—"

"Because the TARDIS is the only other place in the universe where huon particles still exist, thanks, I remember that much. But what's that got to do with anything?"

"Well, huon particles generate fluon radiation, and fluon radiation amplifies and purifies artron energy. It makes the artron stronger, but also more directable – directable enough, in fact, that Time Lords can use artron energy for healing comas and regeneration!"

He spun back around to Rose. "What I didn't know, of course, but my other self did, is that Rose was still carrying some huon energy around in her blood stream after that whole Bad Wolf incident, and that's what's been keeping her alive til now. When my regeneration aborted, I released a wave of excess artron energy, and Rose absorbed most of it, which knocked her out. But her body's dealt with artron before – manipulated it, even, to make changes in time-space. Her subconscious remembers what to do. Even in the coma, her brain's using the huon to direct the artron into healing her cells as they decay under the excess artron energy. She's healing and decaying at the same time, only the decay rate is slightly faster, and she's rapidly losing ground."

Donna looked dismayed. "So what do we do?"

"She needs an infusion of huon particles to give her the boost she needs to purify _all _the artron flooding her system and convert it to healing energy. Theoretically, if we can plug her into a source of huon, she'll be able to come out of it all by herself."

He spun back around and looked at Donna with a manic grin. "And we just happen to be in the one place left in the universe where huon particles still exist."


	18. Chapter 18

They carried Rose out to the control room between them and stretched her out on the jump seat. The Doctor had the additional necessary medical equipment strung under his arm, and he moved swiftly around the console and Rose's chair, setting up an intravenous drip, a toolbox, a rubber hose and a welding mask.

"Okay, stand back," he warned Donna after inserting the IV needle into Rose's arm. He had jerryrigged the IV bag with the rubber hose and a small pump, and pulled the welding mask down over his face. "I'm going to open up the heart of the TARDIS. Don't look in – There's no telling what it could do to you."

Donna gulped and stood back. With a well-aimed kick at a nearby lever, the Doctor popped open the hood, so to speak, and a brilliant white light spilled out into the room. Donna tried to avoid looking directly at it by watching Rose's still form instead, but it was like trying to avoid the sun. A strange, unearthly singing filled the room, the kind one heard with the mind rather than the ears. It reminded her a bit of the song of the Ood, only more peaceful instead of sad.

The Doctor, visor down, bent his head away from the light and reached into it up to his shoulder, placing the hose and pump somewhere inside. Then he retreated back away from the open floor panel and over to where Rose lay.

"There we are," he said, pulling off the visor with a flourish. "The pump should distinguish between huon particles and other vortex energy, and hopefully, we'll see it start flowing any second now. Ah, here it is!"

He pointed out a few tiny grains of glowing golden light as they moved slowly up out of the rubber hose and into the IV bag. Pretty soon the grains turned into a small stream, and the IV bag began to drip golden energy down the line into Rose's arm.

"It's going in. Now we can only wait."

They both looked at each other and then knelt down in unison to peer intently at her at face level.

It was some minutes before anything changed. Then Rose's eyes slowly fluttered open.

"Rose!" The Doctor sat up straighter and gently put his hand to her cheek, but she didn't move or make any response. Her pupils glowed golden as the huon energy flowed inside her skull, filling her eyes from the inside out. Then, abruptly, she let out a breath, a little puff of golden energy which dissipated into the air. She blinked again a few times and then turned her head ever so slightly, meeting his eyes.

"Doctor?"

His face cracked into a wide grin, eyes sparkling with relief. "Rose Tyler. You never cease to amaze me."

"You didn't change…?"

Smiling, he shook his head. She sat up carefully and reached out to his temples, tracing the lines of his face as if to make sure he was still the same man.

"Same brain, same telepathy, same time sense, same sense of taste… not so sure about the hand, though. This one seems newer than the last."

She flung herself at him and wrapped her arms around his neck, crushing him against her.

"Oh, you're back! You did it! You're you!"

"Yeah, I am, yeah," the Doctor nodded as well as he could with his face mostly smashed against her shoulder. His voice was muffled, of course, but the light still danced in his eyes as he peeked over her collar at Donna, who sat smirking contentedly beside them. "Both of me, back to one of me. Strange experience, having double memories. Expect I'll get used to it, of course. Otherwise, less inner conflict than you might expect."

He finally managed to disengage from the hug enough to get a proper look into her eyes again. "But enough about me. How are you? You just absorbed a massive amount of artron radiation, and huon energy on top of that. I should get you back to the infirmary, run some scans."

"I feel great. Fantastic, actually."

"Yes, well, let's just confirm that, hmm?"

Donna piped up. "Are you planning on using the infirmary here, or the infirmary there? 'Cos the other one's a bit messed up after what you did in the control room."

"Ohhh I think the one here will do," the Doctor replied. "I seem to remember stocking it pretty well with supplies on the parallel version of… was it Pen Haxico 2?"

Rose grinned at him, tongue in teeth. "Tropical beaches…"

He grinned back. "Great hospitals. Rather too fond of cyborg implants."

"Right. Well, when you two are done goggling at each other, come get me," Donna said, fondly if a bit impatiently, "I wouldn't mind knowing how the scans check out. In the meantime, I'm finding the loo and a place to take a shower. You got cryo-muck all over me." The Doctor opened his mouth to say something, but Donna waved him off. "No, don't bother. I'll figure it out. The layout can't be that different here; it's grown off the old one, after all. Using my idea. No need to thank me for that, by the way. Just nearly got my brains fried in the process of comin' up with it." Muttering to herself in a grumpy but pleased way, she took the spiral staircase down into the interior of the ship.

They watched her go, and then the Doctor turned back to Rose. "I'd like to scan you as soon as possible, if you're ready. I don't think we should relax until we're more sure of what's going on."

They relocated to the TARDIS 2.0 infirmary and hooked Rose up to several types of scanners. The Doctor perused the monitor, glasses perched on his nose, and made several noncommittal 'hm's and 'ah's as he read the data. Rose watched all this with patient amusement until she'd finally had enough.

"All right, what's wrong with me? You're not saying much of anything and I know you've got ideas."

"Well…" The Doctor settled down backwards on a little rolling chair, folded his arms across the top of the backrest, and rested his chin on them to peer thoughtfully at Rose through his specs. "Nothing is wrong, per se. Just surprising. Very surprising."

"What is it?"

"Well, if you were only lightly seasoned with artron radiation from your travels through time before, you're absolutely drowning in it now. I've never seen any one sentient life form with so much artron built up, let alone a human. Barring the TARDIS, of course."

"Is that bad?"

"Well, that's just it. Your huon levels are also abnormally high, and for whatever reason, your subconscious is controlling it like a regular expert. So yeeeessss, that much artron should be bad, but as long as you're continually purifying it and redirecting the energy into healing energy, I don't see any danger of a cellular breakdown. In fact, rather the opposite."

"What d'you mean?"

"Your cells are regenerating perfectly at a constant rate, rather like mine fresh after a regeneration. It's how your body's attempting to use up that massive amount of excess radiation. But you humans are simple – it doesn't take much to repair you. You have enough huon and artron in your reserves that it could well take you centuries, maybe millennia to run through it all."

"And?"

"And I rather doubt you'll be aging or taking much damage until you do."

Rose furrowed her brow as this sunk in. "Wait, are you saying—"

"You, Rose Tyler, might live longer than me. Well, barring unforeseen accidents, of course. And you should probably stay away from technology that feeds on artron energy. Suck enough of that out of you, and suddenly you have an imbalance in favor of huon particles, and Donna could tell you, that's not all that healthy either—"

Rose launched herself at him, cutting off the rest of his rambling. "Doctor! You don't have to be alone anymore!" She nestled her face into his neck, hugged him with one hand and mussed up his hair with the other. "I'm not gonna grow old and die on you. You don't have to give up being a Time Lord to be human, either. Not that you ever did, you idiot." She kissed him on the cheek.

He smiled back at her, almost boyishly gleeful. "So, Rose! How long you gonna stay with me?"

"Forever!" she laughed, and they hugged again.

Donna walked in with wet hair. "Oh, for crying out loud… You're still at it. Shall I just go, then? Maybe pop in a movie? Is this gonna be a 'Titanic'-length feature, or should I just go straight for the 8-hour 'Pride and Prejudice' mini-series?"

The Doctor and Rose just laughed.

* * *

**Oh no, this is altogether far too cheesy. We can't end on this chapter. Posting the next one right now!  
**


	19. Chapter 19

Hours later, they had picked up most of the mess in what was now being referred to as "the main TARDIS" and transferred Rose and the Doctor's more recently acquired belongings out of their 2.0 room into their rooms in the first one. Donna's room had been pulled out of the hall of retirement and returned to its usual place near the wardrobe room, and she'd gotten changed into something cleaner and softer, which had cheered her up considerably.

"We're not gonna leave the new TARDIS behind?" Donna asked in concern as she entered the control room where the other two were just finishing up repairs to the heaviest fallen cable using the sonic screwdriver and a roll of duct tape.

"Oh no, I could never do that," the Doctor replied blithely. He seemed more relaxed than she'd seen him in ages. "She's just a little baby, alone on her own in the universe, not a single other Time Lord or TARDIS out there to keep her company. She'd wither up and die. No, we're taking her with us."

"And how are we gonna do that? A bit of towing rope? Chain them together?"

"The chameleon circuit isn't broken on ours… er, our younger one," Rose self-corrected with a smile. "We could change her shape. Maybe fit her inside?"

"I like it," beamed the Doctor. "The baby tucked away inside her mother, marsupial style, like a kangaroo. Or maybe a koala. I quite like koalas."

"The main TARDIS won't be just a timeship anymore. We'll have to call her 'the mothership.'"

"Oh, the mothership! That's very good!"

"What shape could we fit through the doors, though? Maybe a smaller box? A refrigerator?"

"Oh no, I'm thinking a nice, large, upright traveling trunk. You know the type, very popular for steamship voyages back in the early 1900s. They had them all over the Titanic. Did you know, I survived the sinking of the Titanic? Both Titanics, actually. There was one more, actually, a starship in the year 5 billion. Haven't been there yet. It crashed too, come to think of it."

"You'd think they'd have learned their lesson with the second, and stopped using that name."

"Yes, well, there was a bit of a revival for old Earth nostalgia during that period, you know. Mind you, the second Hindenberg was a great success. Ran for years before being retired with honors. Some of the biggest parties in the history of the universe were held on that ship."

"Maybe we should give it a go. Think we could get in with the psychic paper?"

"Well, psychic paper's pretty run-of-the-mill by that time. Probably couldn't get us past a security screening. Still, I think I have a trick or two up my sleeve." He grinned mischievously.

"Before we head off anywhere, we're making a stop off in Chiswick, 2009, thanks," Donna interrupted decisively.

The Doctor spun round at her words, visibly deflating. "What? No! Donna, you can't be thinking of leaving…!"

"I'm not leaving, you stupid alien. We're picking up!"

"Picking up? What?"

"Shaun!"

The Doctor and Rose continued to stare blankly at her with an obvious lack of recognition.

"My fiancé!"

"Ohhhhh right, Shaun… Shaun… Temple fellow, wasn't it? Noble-Temple, sounds like a tourist spot."

"It's going to be Temple-Noble! And I'll thank you not to laugh at him. He's coming with us. I'm not watching you two flirt while I sit around like a third wheel. We can double date! It can be your bridal shower gift to me. A pre-wedding honeymoon trip!"

The Doctor breathed in through his teeth and shared a glance with Rose. "Hell of a honeymoon."

"Does sound romantic, though, dunnit?" she smiled back coyly.

"Well, I don't see why not. I'm sure I can think of a few good honeymoon destinations. What do you think of Venice?"

A wide grin on his face, he pushed a few buttons seemingly at random, slammed a lever down, and sent them all hurtling onward through time and space.

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**Thanks for sticking with me through this whole fanfic! :D Stay tuned for the epilogue!**


	20. Chapter 20

…

Epilogue

…

Little did the Doctor realize, dying as he was from radiation poisoning, but when he stopped by Donna Noble's wedding to Shaun Temple and covertly handed her grandfather an envelope to pass on to the bride, he didn't need to make such an effort to stay out of her sight. In fact, not only was she in no danger from the mental overload of reawakened Time Lord memories, she had actually just left a future version of him standing slightly inside the church, making lighthearted quips about the ceremony with the newly returned Rose Tyler.

"See? You made it all the way through the wedding and not a single alien invasion. 'Tuxedo of Doom' theory, debunked." Rose tweaked his bowtie and brushed some lint off a shoulder. The Doctor flinched and looked around.

"Shh! Don't say things like that. The second you say something like that, the universe hears you and decides to bring it all down on your head."

"Since when are you superstitious?"

"I'm not superstitious. I'm a scientist. Science bases theories on evidence, and all the evidence thus far has shown a marked correlation between this particular tuxedo and life and death situations. It's a far higher incidence than coincidence alone can account for. I'll show you the data sometime."

"Correlation doesn't equal causation, though."

"Just because you don't know the reason for something yet doesn't mean there isn't one. Basic rule one of traveling the universe: keep an open mind."

They were interrupted when the bride marched back in to collect them.

"Photos are done!" she announced. "We're heading to the reception. I expect to see you there, not six months down the line, mind."

"Donna, now really!" The Doctor gave her a pained look, and Rose nudged him in the ribs with her elbow.

"We'll be there."

"And don't forget my gift!"

The Doctor raised his eyebrows in surprise. "I already gave it to you."

Donna looked at him blankly.

"It's right there, in, well, you know." He indicated her bosom with a pointed look and a tilt of his head. She gaped, looked at her chest, and then gaped at him again. "I saw you put it there myself," he continued, misconstruing her shock as confusion.

Eyes wide, Donna yanked the already forgotten, crumpled lottery ticket out of her bodice and shakily stared at it.

The Doctor tugged his earlobe awkwardly and rambled on. "Thought I was dying at the time, granted, and that I'd destroyed your life – in retrospect, I may have been overcompensating, should probably take that back, get you a toaster instead—Ow!"

He rubbed his hand where she'd slapped it away from the ticket. "It would have been a sonic toaster!" he whinged.

"Oh, I'm keeping this," she said, smoothing the slip of paper excitedly with both hands. "You traveled in time to get me a winning lotto for my wedding! I bloody love you!" She grabbed his face and messily kissed him on the mouth, at which Rose looked amused, the Doctor looked appalled, and several nearby guests looked scandalized.

Donna released him just as abruptly as she'd grabbed him and ran down the aisle back out the church doors as well as her wedding dress would allow. "Shaun! Shaun, come look at this! Look what the Doctor's got us…"

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**...And that's the end. A big thank you to everyone who read and/or favorited and/or reviewed! :) Writing and sharing this was a lot of fun. I hope you enjoyed it, too.**

**Ta!**


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